UE5 blueprints lose references every time project is reopened

Hi, i’m trying to make a simple shooter game for learning purposes, whenever i close the project and reopen it after a while some of the blueprints are losing the references to “assets” (i.e vfx, Sound Cue, C++ functions), so everytime i open the project i have to fix them before doing anything.

Any idea how this could be prevented? Thanks in advance.