Material instance values getting reset

I am working on a master material and instance, very often some instance material values get reset to some values which are not even the defaults on the master material. It seems this happens when the master material is modified, but there might be other reasons. I had this problem earlier with some materials but this time this is systematic and very annoying. Is there a workaround ? UE 4.18.3.

Save them. Hit the actual save button because a lot of times the save all hotkey doesn’t do it’s job correctly.

It seems to help indeed, thanks @IronicParadox

No problem, good luck!