CPNB intermittent rough idle with injector codes after oil cooler work

Car (15 Q5) went into the dealer for a small coolant leak (would lose about a 1/4 qt a week) that they diagnosed as the oil cooler and was thankfully covered under warranty. When we got home I hooked VCDS up and noticed there were two codes stored in the ECU (no CEL) P020B (8839 - CYL 2 injection timing ) and P245B (18173 - EGR cooler bypass control circuit) and chalked it up to something to do with the repair and cleared them. Later that same day I pulled into the driveway and the RPM's dropped and became choppy and the car started to shake (not really rough, like your on a gravel round), I was in reverse at the time and it did it in neutral and park, brought the RPM's up and it seemed to slowly go away. Now there is a new code for P0269 (19187 - Cyl 3 injector contribution/balance fault - not confirmed) - (still no CEL). I know the fuel system was opened up from the pictures they sent me, could it be some rouge air trapped in the system working its way out?. I'm not able to replicate the cause of it and it hasn't happened while cruising. I want to take it back but in my experience, without being able to replicate the issue they end up turning it back over to you or charge you a hefty diag bill for nothing.

Just wondering if anyone else has had a similar issue or experience.

Thanks
Robert