Bert Coules used his keyboard to write :
I have a perfectly standard mid-range kitchen mixer tap. Just recently, it's
taken to releasing a short (around one second) stream of water (from the cold
side I think but I'm not sure) when it's turned off. Sometimes this happens
directly after the tap has been used, sometimes completely at random.

It's almost as if there's been a sudden increase in pressure which forces the
water momentarily past the tap's mechanism, but it's happened so often that
this seems pretty unlikely, even if it wasn't unlikely in the first place.

So what might be the cause? And should I be concerned and try to do
something to stop it happening?

Most likely - the cold water still in the neck, expanding as it warms
up, then dribbles.

My electric shower does the same - cold water in the hose warms up to
bathroom temperature, then dribbles out of the head.