As reported by [teslarati]:
The news has come in that the apparent cause of the engine malfunction may likely have been the force of the Raptor engines destroying the ceramic coating on concrete test pad for SN8, causing debris to sever the avionics cables and resulting in the malfunction. One of the Raptor engines has been swapped out and some further adjustments for shielding the avionics within steel pipes, and water cooled steel pipes may be fitted for future testing to help prevent a recurrence of the issue. Given that this may not have been any serious issue with the engine itself, it seems that testing is set to continue with a minor delay.