Broken/Gray shaders - Broken material instance - gray checkerboard material instance. Uncompiled shaders

I have a sprite material for realtime VFX. The SPRITE Material is using a regular texture - not any “virtual texture”. I’ve made a material instance. This material instance is hooked to niagara-system . When the VFX fires during gameplay- I get gray checkerboard planes displaying instead of my propper VFX sprite that i’ve made. When I go to see the material in content browser → it looks gray → like in the image i inserted. To solve this I need to open the texture again OR toggle some settings in the material instance OR re-apply my mastermaterial (parent material).

This happens every time i reboot unreal engine. THIS IS NOTHING NEW IT SEEMS -AS I’VE GOTTEN THE SAME ISSUE ONCE BEFORE IN 2024. What is the issue??