Misfire Damaging to Cat P0300 & P0305
 

I received a check engine light last night

P0300 Porsche Fault Code 63 - Misfire damaging to cat converter

P0305 Porsche Fault Code 67 - Cylinder 5 misfire damaging to cat converter

I replaced my spark plugs a few days ago with no issues. Car ran well.

I did a coolant flush on it last night and while doing the whole process revving the car and what not during the bleeding part. The light came on.

It flashed and stayed solid. I turned off the car, double checked the coils if they were plugged in. Went home and parked it. This morning I woke up and reset my engine light with the durametric. Took it out for 20min for a spirited drive and car seems to run well after the reset.

What triggered it? Could the problem still be there?