Emissive material stops working after color change

Hi there :slight_smile: I have an emissive material with a vector color parameter, and have a function in my level blueprint which changes its color via dynamic material instances. It works, but only exactly one time for some reason. I can change it to any color, for example red (first picture below), and it changes, but when I call the function again, even with the same parameters, the material kinda just shuts off and becomes dark (with some weird noise-texture on it, but that may be unrelated) (second picture below).
Nothing is adding or subtracting or anything like that in the function, everything is refreshed from absolute set variables.
I don’t get why this is happening… Anyone can help me with this please? Thanks!