Yep that’s possible.
If they want to isolate the avcs issue a simple test is to swap them from one bank to the other.
If the issue follows suit, the problem is with the affected ocv. If they replaced one, mark it so you know which is which.
It’s about 1-2 hours labour for the job.
If the issue persists after the test on the affected bank, it’s going to be an issue with the adjacent cam gear or the oil supply to the filter: banjo bolt filters quite deep in the oil gallery under (or in) the banjo bolt.
But hopefully it’s not that.
Personally I’d say, since you seem to be going in circles here, take it to a Subaru specialist, not a dealer or random mechanic. Or read the related diys as this is all possible with basic tools.
Read about it here:
https://www.google.com.au/search?biw=32 ... KAjM38LstcLet me know if you’re still struggling plus your location.