When modifing the Game Shaders using a Resource pack any error will be logged to console, but no fallback to default resources is triggered. Also, the Shader stays unloaded Permanently. Even after Removing the Resource Pack the Shader will not reload.

Only a Game Start can reset this, which is extreamly annoying.

Also, whenever the resource pack is reloaded after this bug was triggered, the attached error will occure.

Also, Errored Shaders will lead to the Game throwing  more errors from other places referencing the unloaded Shader.

There can even happen stuff like in latest.log. (i also attached the Pack that i used when latest.log happened)