I have that monitor it happened to me too but the burns go away after a while, you can accelerate the process by playing an RGB ‘cleaning’ video from a file or even YT.
That issue wasn’t too common in the past but today it happens to all IPS panels all name brands, no exceptions it seems.
On that monitor I don’t use the OSSC for playing sources that are interlaced at all times (like most PS2 library) and therefore require constant deinterlaced output, so I never meet the dreaded flickering for longer than a few seconds or minutes within games that have like interlaced ingame menu screens, or progressive but fast flickering items (e.g Progear title screen), none of these are a problem unless you leave these particular screens to display for too long.
If one seeks a LCD that doesn’t have this temporary pixel marking/retention weakness, then it has to be a VA, ViewSonic don’t have a large one that would be identically as good and convenient as the VX3211-mh in 32″ size, they do have 27″ but all curved AFAIK, except the VG2739 which is rather old and lacks enough info to recommend. Maybe they have a good 24″ VA idk.
(NB: rare cases of VAs marking to flicker have happened though, I think I’ve seen a couple of cases on rtings website, but that wasn’t much)
Other brands I don’t really care about since for the OSSC I don’t believe there are any making monitors offering as much convenience, compatibility and quality for the original OSSC than those select ViewSonics (that mostly won’t matter later with the OSSC Pro but for now that’s the status)
Maybe there are a couple VA models out there from other manufacturers that handle everything as well in the ViewSonic fashion, but that’s impossible to guess without users specifically trying them with an OSSC and reporting to the community.