Missing Assets! Flipbook's have removed sprites, but some sprites still remain!

So I was working on my animations the other day, importing sprite sheets and making the flipbooks for a 2d base, had them all running fine, saved closed reopened, still all fine, happy days!

I open it up today, and some of the sprites/flipbooks have gone blank, but what doesn’t make sense is that for my “Jump” sprites folder for instance, Jump ‘6’ was still there… Same with “attack”, one sprite still left behind, and for some reason my “Run” flipbook is completely untouched, although it’s located in the same places as the others and created just after “Idle” and before the other flipbooks which are all gone…

Seems very odd that its been closed before and re-opened and worked but now just a few days later it’s all gone kaput. Any help would be great, I’ve had this happen with tilemaps before aswell and that’s just randomly stopped happening even though i’ve not changed implementation…