Apple Watch series 3 screen shot when pausing swim workout - fix?

When pressing both buttons during a swim workout to pause it (as per the instructions) it also takes a screen shot. This is really annoying as I end up with loads of random photos of rubbish swimming stats that I then have to go and delete.

Any one suffer the same/found a way to stop the this happening? Is it a known bug? I don’t think it is user error.