CEL flashing and... gone. P0304 pending

[PLP]

Conditions.
Fully warmed up, after about 20 some miles drive. Driving between stupid speed bumps. I stayed in the 1st gear, pushed to about 5000 rpm and then slowed down.
Somewhere there the CEL started flashing. Engine did not complain. Was smooth and quiet.

Then the CEL, after flashing a few times - less than 5 seconds I would say, stayed off. Engine, again, was smooth and felt powerful. Just normal.

Drove to the destination. Parked. All OK,
Checked codes - Pending P0304.

I cleared the code as I think it is a one time flux due to my weird behaviour.

However, is there anything else I might be missing?
Maybe it is an underlying condition for something bigger?

Tell me if that could lead elsewhere...

Sparks and coils have supposedly been changed about less than 5k miles ago, meaning I put about 3000 while the repair was done 2000 earlier.

So, any warnings or keep going do not worry.

No morning smoke, except occasional puff after longer storage.
No water in oil.
Smooth on cold start and smooth all the way.
Coolant clean and no leaks.