Graphics reset to high quality though lower option is selected; game gets laggy when I try to rectify

Platform, device, OS
Android, OnePlus 8T, Android 11 / Oxygen OS
Also for reference I am on 0.35.11105 according to the game settings.

What were you expecting to happen, and what actually happened
Expected: Once a graphics level is selected, it should persist indefinitely.
Actual: Although my graphics are set to low or very low quality, sometimes the visuals randomly go back to very high quality. If I go to the display settings, low or very low still appears to be selected. If I select the opposite of the two lowest settings (e.g. go from low to very low) and apply the setting, the quality drops back down, but usually the game gets incredibly laggy to the point of being unplayable, and I have to force quit and restart the game.

How often does this happen? When did it begin happening?
This is happening regularly. Possibly every 1 or 2 days. There is no discernible pattern to when it happens other than that it seems to happen while the app is already open and active, and I think it happens when a new battle starts, but I am not sure about the last part. It doesn’t seem to be correlated with game updates. It has been happening for at least a couple of weeks.

Steps to make it happen again
I have no idea how to reproduce, given that it seems to be pretty random.

I think the graphic appearance vs. actual setting mismatch persists if I merely restart the app, and is only cleared out if I do a quality setting swap as mentioned above.