Unable to revoke Kraken (KRAKEN) token approval on Ink mainnet (approve(spender, 0) always fails)

[schoolkamsergj]

Summary

I am unable to revoke a token approval on Ink mainnet for the Kraken (KRAKEN) token. Calling approve(spender, 0) consistently fails with an "internal error" in multiple wallets and UIs, so the allowance for this spender remains a very large uint256 value (effectively unlimited).

I’m reporting this here in case it is related to Ink infra / RPC / explorer integration and not only a third‑party wallet issue.

Network

• Network: Ink mainnet

Addresses / Contracts

• Owner (my EOA): 0x521D78818f6F96D8AcbAD527fB18D8a01319c9b7
• Token (Kraken / KRAKEN): 0xCa5f2cCBD9C40b32657dF57c716De44237f80F05
• Spender (DYORSwap router / contract): 0x9b17690dE96FcFA80a3acaEFE11d936629cd7a77

What I see

1. On the Ink explorer (Blockscout UI) under Contract → Read/Write contract for KRAKEN, calling:

   • allowance(owner, spender) with the above addresses returns a very large uint256 value (unlimited approval).

2. When I try to revoke by calling approve(spender, 0):

   • Via Revoke.cash on Ink
   • Via Ink explorer Write UI for the KRAKEN contract
   • Using several different wallets (Rabby, OKX, etc.)
   • Using the official Ink RPC endpoints

   the wallet shows an "internal error" and the transaction is not broadcast (no tx hash is created). The allowance value does not change.

3. Other transactions on Ink from this address work fine, so it doesn’t look like a general network or nonce issue for my account.

Why this matters

Because the allowance is still unlimited, if I ever receive KRAKEN on this address again, the spender contract theoretically can move those tokens. Right now my KRAKEN balance is 0, so there is no immediate loss, but it is impossible to properly revoke this approval and clean up wallet permissions.

What I expected

• approve(spender, 0) on the KRAKEN contract should succeed and set the allowance for this spender back to 0, like a normal ERC‑20 approval revoke.

Questions

1. Is there any known issue on Ink mainnet (RPC, gas configuration, or explorer integration) that could cause approve(spender, 0) on this token/contract to consistently fail with "internal error" in multiple wallets?
2. Is this behaviour expected for this token (e.g. non‑standard ERC‑20 implementation) or something that should be investigated as an infra issue?
3. Is there any recommended workaround to safely revoke this approval on Ink, short of abandoning this EOA for KRAKEN?

Happy to provide additional logs, screenshots or to test specific RPC endpoints if that helps. Thanks!

[schoolkamsergj]

[schoolkamsergj]

@schoolkamsergj have you been able to resolve this issue?

Hi @paulasummith-DEV — unfortunately no, I haven't been able to resolve this yet.

My current understanding is that the issue is likely in the KRAKEN token contract itself (non-standard ERC-20 implementation that blocks approve(spender, 0)), rather than Ink infra. The Ink RPC and other transactions work fine for me.

For now the only practical mitigation I know of:

Current KRAKEN balance is 0, so there's no immediate risk

Avoid receiving KRAKEN on this address in the future until this is resolved

If anyone from the Ink/DYORSwap team has insights on the token contract behaviour, that would help clarify whether this is fixable on the infra side or purely a contract issue.