Duplicate and missing compatibility entries

In my game list Knight's Contract returns No results found under Compatibility. I checked the list online and it only has the EU serial and not the US one(BLUS30582).

I also noticed that some of the Tales of games have duplicate entries, so depending on which version you have it would either display Playable or Ingame, though I'm told the versions are identical in the discord.

The game is not on our compatibility list, you need to make a game report
https://forums.rpcs3.net/thread-196671.html

Is there some significant difference between different versions of the same game? I see plenty of other games with several regions worth of serials.

Is there some significant difference between different versions of the same game? I see plenty of other games with several regions worth of serials.

Normally the only difference I've found is language options.

Yes, different versions can often contain different game code, such as an updated base version (even if it shows 1.00 on both)