Broken materials due to sudden linear color/color changes

I am working on a Unreal Project with some collegues. Since last month, out of nowhere our materials are broken.

Out of nowhere some texture nodes have a diffrent sampler type (Linear Color of Color)
We can fix this by pressing the magnifier icon and then the arrow icon at every texture/node. We just have no idea why this is happening. Is also quite frustrating since we sometimes use many nodes. Does this has to do something with migrating scenes or source control?

We are wondering if other people are experiencing this problem as well.