Darker wall colour showing through that looks like a damp patch but isn’t. (Photo included)

[Ltnman]

Kitchen cupboards have been in place a good 10 years with the walls repainted with a mat emulsion a couple of times over the years.

I am noticing what looks like a damp wall next to the cupboard but the wall is a stud internal wall with no pipes or radiators on either side of the wall. The ceiling is dry with the darker colour starting just below the ceiling and ending just above the tiling. What is going on, is it an issue with the silicone, and can I just paint over it?

 

[Wayners]

Condensation forming behind cupboards because of a lack of air movement maybe?
Built in wardrobes don't have backs on because of condensation and mould forming behind.
You need to have a look to confirm.

 

[RandomGrinch]

What is going on, is it an issue with the silicone, and can I just paint over it?

IMHO, it looks like bleed out from the silicone.
I would remove the existing silicone and monitor.
If the shape/colouring of the patch changes, the issue may be damp. If nothing happens, the absorbed silicone needs to be cleaned off.