Digital 'Ink blot' at end of strokes when painting in Photoshop

[Rakutempo]

Hello everyone,

I'm hoping someone has an answer to this and will do my best to describe the problem. I am experiencing a maddening problem with the brush tool that I can only describe as the digital version of a fountain pen dropping a splodge of ink at the end of a stroke.

When I am using the brush with 'Pen Pressure for size" checked, at random intervals at the end of a line it will drop a square of pixels. I have taken some pictures to show what I mean

 So far I have tried reverting from CC 2020 back to CC 2019, I spent hours on the phone to technical support where he changed all my settings, (and ultimately did a factory reset), tried putting ".old" at the end of files in the Preference pane. I have also updated my Wacom tablet drivers.

It only seems to hapen with this one brush, which is the 'DG Main' from Dave Greco's brush pack in case anyone has the same. I know the obvious answer would be to change brushes but this is my favourite brush and there must be an answer right? Here are screen grabs of the brush presets

I am working on a Late 2015 Macbook Pro Retina (13 Inch) and a Wacom Intuos Pro.

Any advice would be hugely appreciated. This problem is driving me insane

Many thanks

Ben

[Rakutempo]

Just realised I should probably also say I'm on Catalina 10.15.7 but this has been going on for far longer than I've been on this OS