Ilogical error when calling getConflictingBundle - Error: Target bundle errors at top of block

I am trying to use getConflictingBundle endpoint and always get this error when my txs are 100% sure not reverting, doesn't make any sense .

1) when same tx sent to mainnet without any relevant state changes there are no reverts
2) when simed in tenderly no reverts
3) when siming with flashbots all good.

With getConflictingBundle however, this error happening almost everytime , even for bundles which were included!

What's this all about ? There is nothing on the documentation providing insights into this but seems like some issue with the way flashbots is simulating the transaction ?