Is there any correlation with the the preset used?
Do you have a tablet?
If yest to the tablet, are you using Lazy Nezumi Pro?
I do not use a tablet. I don't understand what you mean by correlation with the preset? Even when I use standard brushes, this happens.
I meant is the a link with the issue happening with specific brush presets.
Try resetting All tools. (top left corner of Options bar.
If that does not help, I'd be inclined to reset Preferences. I hate suggesting that as it is a pain, but the inconsistent nature of your issue has a Preferences feel to it.
...............and my brush is large.
How large. If the brush is large and you zoom in, so that the circle would be bigger than the screen, you get the crosshair instead to show the centre.
That seems to have worked. Does that mean there's something wrong with one of my presets?
just restarting PS solved the problem for me.