Multisig calls from Polkadot.js on Polkadot AssetHub do not commit call data onchain

[CoinStudioDOT]

After the Polkadot AssetHub migration, multisig calls created via Polkadot.js Developer - Extrinsic are no longer committing call data onchain.
Only the call hash is stored, which makes these multisig calls impossible to approve.

This issue seems specific to Polkadot.js on Polkadot AssetHub:

• Polkadot.js multisig calls work correctly on Kusama AssetHub, where call data is committed.
• Multisig calls created using the Mimir wallet on Polkadot AssetHub work as intended and include full call data.

Examples

❌ Polkadot.js multisig calls on Polkadot AssetHub — missing call data

• https://assethub-polkadot.subscan.io/multisig_extrinsic/10624163-5?call_hash=0x8a7a8c6bc6cb154ea0430cd7de9c6fdd9b97df90051a183a2e063c6258188453
• https://assethub-polkadot.subscan.io/multisig_extrinsic/10633570-2?call_hash=0x4c8a2f85b34aecb528f563349dd80b3e502e4d3504e5098269489e75c8a11af5

In both cases, only the call hash is recorded, the call data is not committed.

✅ Mimir multisig call on Polkadot AssetHub — call data committed correctly

• https://assethub-polkadot.subscan.io/multisig_extrinsic/10638593-3?call_hash=0x579c52e65e1213966c42a25c4d807933ad8d2ac30f309cc9ee396d371f6ebea8

This shows AssetHub supports multisig call data correctly and that the issue is specific to Polkadot.js submissions.

✅ Polkadot.js multisig calls on Kusama AssetHub — working as expected

• https://assethub-kusama.subscan.io/multisig_extrinsic/11860890-2?call_hash=0x12064a77237278e1472d3f6fb921c8547c09eb888730563cc059e9735d95635d

This shows that Polkadot.js multisig extrinsic is functioning correctly on Kusama AssetHub.

[rajk93]

@CoinStudioDOT I reproduced the issue on Polkadot Asset Hub using a forked environment(chopsticks) on Apps. I performed a simple balance transfer from a multisig account with 2 signatories, providing the call data during the second authorization extrinsic. It's working as expected.

I've attached a preview of the flow as well. Please let me know if there's anything I might have missed.

Screen.Recording.2025-12-08.at.1.30.12.PM.mov

[CoinStudioDOT]

Thanks for checking this, much appreciated.

multisig calls created via Polkadot.js → Developer → Extrinsic are no longer committing call data on-chain.

This is the specific flow where the issue occurs, not the regular UI flow you tested.

The behavior has been reproduced independently by two different curators, on two separate bounties, both using raw calls submitted through Developer → Extrinsic in Polkadot.js.

This multisig is a bounty account, and all multisig operations are executed through its dedicated bounty proxy account. It is possible that the issue is related either to the multisig itself or to the associated proxy account.

Below is the exact raw call that results in call hash only, with no call data stored:

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

[rajk93]

Thanks for providing more context!

I tried to reproduce again by submitting a multisig extrinsic through Polkadot.js → Developer → Extrinsic on Polkadot AssetHub, but it worked as expected on my end.
I also reviewed the codebase and couldn't find any AssetHub-specific logic that would prevent call data from being committed.

[CoinStudioDOT]

There is definitely something off here, more likely related to how Polkadot.js wraps the call incorrectly when using a proxy, rather than an issue with multisig itself.

To help debug, I’ve issued two separate calls using the exact same call data, one through Polkadot.js and one through Mimir.
The difference is very clear:

• Call issued through Polkadot.js:
  https://assethub-polkadot.subscan.io/extrinsic/0xd51dcc6e2fbf631ad5ef44fae759fcca06f02bca17c823a3967dc10215379313
  → No call data committed

• Call issued through Mimir:
  https://assethub-polkadot.subscan.io/extrinsic/0xbfecc237afd33451aca8a846a187c440bfcbc88de1532d2058da2a5e0ce9353d
  → Call data committed correctly
  MIMIR calls

[rajk93]

Hm, Looking at this more closely, I notice the two calls are actually using different extrinsics:

1. Polkadot.js Apps: multisig.approveAsMulti - This only registers approval for an existing proposal without attaching the call data.
2. Mimir: multisig.asMulti - This submits a proposal with the full call data included.

If you'd like to use asMulti directly in Polkadot.js Apps, you can do so via Developer → Extrinsics → Submission. Select the proxy account, choose the multisig pallet and asMulti, then construct the call with the required parameters.

That said, if this doesn't match the issue you're experiencing, a screen recording reproducing the problem would help in clarifying few things.

[CoinStudioDOT]

Using the same proxy account and submitting the same extrinsic logic from both Polkadot.js and Mimir results in two different call types being created:

• Polkadot.js → generates multisig.approveAsMulti (missing call data)
• Mimir → generates multisig.asMulti (full call data included)

This happens even when the intention and the input parameters are identical.

To repeat the previous messages:
Using the same parameters and the same proxy setup, Polkadot.js and Mimir produce different extrinsics.
One commits call data, one does not.

[CoinStudioDOT]

@ap211unitech Can this have reference to #12051 and

Issue was in the logic how it finds available proxy types

[ap211unitech]

@CoinStudioDOT I verified that issue yesterday. It was there for Polkadot Relay and Kusama Relay only, it wasn’t related to any of the Asset Hubs.

For this particular issue, Polkadot.js Apps sends exactly the same call that you build on the Submission page; it doesn’t add any additional wrappers.

Mimir might be wrapping a multisig or proxy call around the original call to abstract away complexity. When your wallet asks for the signature, can you verify what call you see there?

If you want to submit the call through Polkadot.js Apps, you’ll need to construct the full call manually.

[ap211unitech]

Call issued through Polkadot.js:
https://assethub-polkadot.subscan.io/extrinsic/0xd51dcc6e2fbf631ad5ef44fae759fcca06f02bca17c823a3967dc10215379313
→ No call data committed

Call issued through Mimir:
https://assethub-polkadot.subscan.io/extrinsic/0xbfecc237afd33451aca8a846a187c440bfcbc88de1532d2058da2a5e0ce9353d

Also, from the links you shared, it’s clear that one call uses multisig.asMulti (Mimir) while the other uses multisig.approveAsMulti (Polkadot.js Apps). Polkadot.js Apps only sends the call exactly as you construct it. This means that if you want to use multisig.asMulti, you need to build that call explicitly on the Polkadot.js Apps Submission page.

Also, as @rajk93 said, having a screen recording here explaining the issue would be very helpful; it will help us understand the issue better.

[CoinStudioDOT]

Sharing the video as requested:
Google Drive

We are manually building the full call exactly as we have over the last 4 years, but Polkadot.js no longer handles it correctly after the AssetHub migration. At the moment, the only reliable workaround is using Mimir because Polkadot.js appears to have an issue processing proxy → multisig calls on Polkadot AssetHub.

Mimir
Mimir call
Polkadot.js call

[rajk93]

@CoinStudioDOT Thanks for the screen recording, it was very helpful in reproducing the issue.
I’ve opened a PR to address it: #12062 .
Once the PR is reviewed and merged, you’ll be able to verify the fix.

[rajk93]

Meanwhile, if you have some time, you can also test the changes locally by following these steps:

1. Clone the repo:
   git clone https://github.com/polkadot-js/apps.git

2. Check out the branch:
   git checkout rk/fix-multisig

3. Install dependencies:
   yarn install

4. Start the local server:
   yarn start

This will start the UI on port 3000, and you can access it at http://localhost:3000/.