Image animation error in The Happy Fun Game

Hi, I’m reporting an error for an old game called The Happy Fun Game, made in 2k3. During an early boss fight, the boss’s sprite disappears and then slides to the side while reappearing, as shown here using the base RPG_RT.exe.
However, when using the continuous build of EasyRPG Player, the sprite instead reappears in the exact same spot even though its actual position is to the side; it will instantly reappear when the real spot is attacked, as shown here

The game can be downloaded here if you need to reproduce the issue: www(dot)dropbox(dot)com/scl/fi/7s10y19zbujwqe9u450m0/THFG_10_10_2017.rar?rlkey=0xzaa1aqsu5bcfqytuak8y4a1&e=1&dl=0
A save file directly to the left of the boss room is available here: files(dot)catbox(dot)moe/lg94tt.lsd (pressing numpad period is the attack button)
Had to replace the .'s with (dot) because I can only post two links.

www.dropbox.com/scl/fi/7s10y19zbujwqe9u450m0/THFG_10_10_2017.rar?rlkey=0xzaa1aqsu5bcfqytuak8y4a1&e=1&dl=0

Save01.lsd (193.8 KB)

Thanks for the report. We track this here: The Happy Fun Game: Boss does not move (not bug compatible) · Issue #3354 · EasyRPG/Player · GitHub

We detect the engine used by the game and emulate certain bugs. This game uses a late 2k3 1.0.3 RPG_RT and we consider a bug with pictures fixed in 2k3 1.0.5. So we must adjust our heuristics here.

Until we fix this as a workaround you can delete (or rename) the RPG_RT.exe. When the file is missing we assume that the game was made using a more recent version of the engine.