Bitcoin has a consensus rule that limits the number of stack items in a row to 1000. However, a P2TR spend containing OP_SUCCESSx precedes this rule regardless.

I made a P2TR spend containing an OP_SUCCESSx opcode with 500,001 empty pushes, which as a result, caused a consensus conflict between btcd and core:
https://blockstream.info/tx/73be398c4bdc43709db7398106609eea2a7841aaf3a4fa2000dc18184faa2a7e

Changing the maxWitnessItemsPerInput parameter from 500,000 to 4,000,000 solves the issue:
https://github.com/btcsuite/btcd/blob/master/wire/msgtx.go#L103