Key feels like a sponge

One of my keys started to feel a little bit like a sponge and less clicky than the other keys (sorry for the wierd descrption XD). It is the tab key which I frequently use. It still works, but requires much more force to press.
Does anyone have an explanation and a possible fix for this?
For kontext the keyboard is about 1.5 years old.

Check if there is not food or something else stuck insideā€¦

Okay it seems fine now, maybe it recovers after pressing it multiple times.