When my arrows aren't hitting where they should, it is more likely that I have gotten lazy from shooting a lot of arrows, and I’m doing one or more sloppy things: not hitting my anchor, not getting my elbow behind the arrow, letting my string elbow droop, my concentration is drifting, not following through, creeping, etc. After going through my checklist of horrors, I can usually get the arrows back to hitting where they should again.
I think really good shooters find something that works and stick with it. As soon as I find something that works, I try to make it better, so I’ve probably never really developed an ingrained instinctive aim that I can revert back to.