My son is assessing Affinity Photo for Windows as a replacement for Photoshop now he has finished university (44 days left on the trial version).
He uses Affinity Photo with a Ugee M708 graphics tablet. As soon as he updated to 1.8.4, he had all kinds of weird problems; lines with gaps appearing mid flow, lines drawing themselves in the corners etc.
In the end, after reading that others were having problems with other tablets, we down-graded to 1.8.3 and the problems were solved.
This is most definitely a problem wit the new update and I hope that it will be resolved soon.
He has been more than happy with Affinity Photo up until now.
P.S. I own Affinity Designer (Mac and iPad) and couldn't do without it!