It is due to the different contract / internal transactions, and hard to decode the transactions because it’s an unverified contract.
I think we might have to switch to indexing by contract events rather than transactions, since internal transactions do emit events on the official ENS registrar. But these events don’t include the secret, so we’ll ultimately still have to get it from the transaction itself. I can think of a hacky way to do this just for ens.vision, but ideally we don’t have to handle each contract individually.
I’m talking to the sort.xyz team to see if they have ideas, or I can probably build a custom indexer and include it in the same open source repo.