Arbitrum eth_getBlockByNumber omits `l1BlockNumber` field

This just broke Livepeer for anyone using Infura Arbitrum nodes:

curl --silent -H "content-type: application/json" -X POST --data '{"jsonrpc":"2.0","method":"eth_getBlockByNumber","params":["latest", false],"id":1}' https://arbitrum-mainnet.infura.io/v3/<api key> | jq '.'

Infura does not return a l1BlockNumber there. Our self-hosted nodes do. Arbitrum’s first-party nodes do. Alchemy’s nodes do. Infura’s did… until earlier today, apparently? Was there a recent change here?

Hi @iameli and welcome to the Infura community!

The team is working on the fix!

@iameli, the fix was put in place and deployed.
I have tested myself and it works as expected.