I would guess that this module needs replacement, but before you do that:
– Do you have a L8xES processor next to the L8SP?
– Was the L8SP firmware updated at the same time you flashed that L8xES processor?
– Was L8xES processor program configured for SIL3 partner use? It will not work if loaded code is for SIL2
– Did you pull all modules out of this chassis and inspected connectors for bent pins?
If this did not help, then time to call your local distributor to get replacement.