6x charge cable connection issues

I have had my 6x for a few weeks now, and I am finding that the charge cable is no longer working reliably. If I plug it in, you do not get a charge indication most of the time. I can wiggle the cable about a bit and sometimes it will work.

I have bought a couple of extra cable off ebay and so far they seem to work, at least most of the time.

I suspect that the pins in the watch are getting dirty or something? They look ok, but who knows?

Is this a problem generally?