Blueprint Interface won't save progress; function reseted all the time

So i have a Blueprint Interface with some functions created to connect a Damage/Attack/Heal system.

Today i created a new function with one boolean output, then i implemented the new function (very basic) however, the engine wont save the progress for some reason. File > Save All does nothing and there is no “You have unsaved changes” or whatever, but if i close the project to open it again, the function is empty

I tried to remove the function, but the new one has the same problem