Confirmed for 1.16 - however, I dont believe what Energyxxer said above is entirely true. I did some testing and it seems the TileX, TileY, and TileZ values (lower left corner of paintings) never actually gets changed or updated, only the Pos does. You can verify this using the data command or by leaving and rejoining the world, which will reset the painting back to its original location.
Hello, I think I may have just misunderstood the way the predicates work, please feel free to close this issue. Sorry!