This method cannot return null. Not exactly sure what it's supposed to return, but it's not supposed to return null. Easiest fix would probably be to change it to a reload listener that doesn't have to prepare.

Seems to be specific to Forge.

Both resource pack and shadow pack with optifine.

It crashes every time I switch shadow pack or resource pack.

It happens on 1.18.2 with latest Forge and Optifine.

Should be fixed in the newest version.