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?

Many thanks.