Ok so here’s what stands out to me as a good place to start base of the brief outline you gave and my experiences teach a couple thousand students over the last 10 years.
1. Make sure you’re firing statistically significant strings and series of fire to confirm POI/POA. 50 rounds over two trips (assuming you did more than bag away at just the 200y) isn’t much.
Shoot a 100y 5x5 without making any adjustments, getting up and breaking position between each 5 rounds, at your a sustained rate of fire and see what happens. Your 25 rounds should share an overlaying of POI in relationship to the POA or you may notice your POI isn’t actually where your POA was.
Additionally this could also highlight a possible “wandering” POI which is like related to improper fitting of the rifle to the shooter and/or poor fundamentals of marksmanship, particularly regarding body position and sight alignment.
A poorly fitted rifle or improper parallax can easily cause 0.1-0.3 shifts in your POI
2. Mechanical issues may be at play. Failure to properly mount, torque, locktite optics are very likely to cause issues at some point.
Lose bipods can also cause shift POI as well and the advent of lighter weight rails and flex under load can also cause POI shifts.