Outside of Schrader valve is inflating. This isn’t right, is it? My wife has an old Moulton bike. I was inflating her tyres (small wheels, tyre imprinted ‘50 pounds’, when the rubber surround of the Schrader valve started inflating also.

It all seems quite airtight, but I don’t think it should do this, and I wonder why it is happening, and what I should do - replace the inner tube, or just let it get on with it?

I don’t want it to blow out when we are a few miles away from home.

Anybody seen this? Any thoughts and advice?
I haven't come across this before but it's not right. It sounds like the valve coating is coming unstuck from the metal part of the valve. If that fails it would be quite likely to fail suddenly which could be painful. Time for a new tube