[1.12.2] Animated textures don't get loaded in subfolders

[MasterBuilder747]

I wanted to use subfolders in my modpack due to the high amount of textures in my pack. However, when I came across animated textures, when using subfolders, they did not get loaded:

• items/upgrades/inf_upgrade0 (the non-animated texture) works
• items/upgrades/inf_upgrade (the animated texture) does not work
• items/inf_upgrade works

In the latest.log, the wrong file path is assigned, and the subfolder is ignored, assuming its in the root items folder, therefore resulting in a filenotfoundexception