ᐅ Room thermostat damp on the front surface

Hey,

does anyone have an idea about this? Recently, I noticed that the (always closed) room thermostat in the bedroom feels damp on the front side, where the adjustment dial is—there is a moist film on it. Below, on the wall/wallpaper, there is a damp spot. I have never experienced this before, not with any other thermostat.

Thanks!

What kind of wall construction is this? Could there be drafts coming through the hole in the wall?

@lastdrop
I don’t think so. Interior wall to the hallway on the upper floor, brick. After living in the house for 3 years, this is the first time I’ve noticed it.