Etherscan verifcation not working

[heueristik]

I tried verifying the EvenNumber.sol contract that I've deployed to sepolia using

➜  risc0-foundry-template git:(main) ✗ forge verify-contract ${EVEN_NUMBER_ADDRESS} --rpc-url https://eth-sepolia.g.alchemy.com/v2/${ALCHEMY_API_KEY:?} --verifier etherscan 
[⠊] Compiling...
No files changed, compilation skipped
Start verifying contract `0x998A5735633afc905d542a97C9C2Dd664394e397` deployed on sepolia

Submitting verification for [contracts/EvenNumber.sol:EvenNumber] 0x998A5735633afc905d542a97C9C2Dd664394e397.
Submitted contract for verification:
        Response: `OK`
        GUID: `kc2hwswvs7wxnznyww6ufes8ni4sgek4zsij5dvtidleaskx1b`
        URL: https://sepolia.etherscan.io/address/0x998a5735633afc905d542a97c9c2dd664394e397
➜  risc0-foundry-template git:(main) ✗ 

but doesn't verify the contract (see https://sepolia.etherscan.io/address/0x998a5735633afc905d542a97c9c2dd664394e397).

This doesn't change if I execute the command from the root instead of the contracts directory.
This problem seems to be caused by ambiguous import paths as per the foundry book

[linear]

WEB3-325 Etherscan verifcation not working