No, it's an innocent explanation.
The valve stem bodies are a type of brass. Any other metal left in contact and then subjected to weather s3nd road salt will corrode and lock solid.
Its not an unusual occurrence. Fairy easy to remedy. Your local tyre place would charge probably a tenner or so per wheel to sort it.
Going on for 3 months after i found they wouldn't come off,i had them removed yesterday! I took the car to a local tyre centre and was told it'd take about 20 minutes and cost 20 quid (thinking i should've applied that £1 a minute rate when i was window cleaning!

). When i asked if card payment was ok he said he preferred cash.

So i walked to the nearest cash point to draw 20 quid out and walked back to see my car was waiting for me.
A lesson learnt! Never again use metal valve caps!🧐
Forgot to mention. He blew all 4 tyres up to 32 psi,which he said was better than my 35 psi...and i got 4 'free' pastic dust caps,so we all went home 'appy!
