I just started seeing this error by the dozens a few days ago on flows that previously did not report it.
"Unable to process lookup search key for field \"Id\": Missing helper: \"id\""
I am unable to ascertain it's meaning, as all the json blocks have id fields. It happens on unrelated flows, one for opportunity to order, SalesForce to NetStuite, the other on NS item to SF product. If I do a retry, it seems to resolve.
Thanks for letting us know about this. We're not sure on this, so we've created a support ticket for this for you - can you please add detail to this ticket? Thanks so much and have a great day!