I have Affinity Designer 1.8.3 (latest stable), and I experienced this bug since 1.8
When Artboard is selected and I want to rotate it with "Move tool", it doesn't show the "rotation marker", by which I can rotate it. It appears only when I start moving Artboard with Move tool.
Little bug but annoying sometimes, especially when you have lots of content inside artboard!
My specs (ask me if you need more):
Mac OS Catalina 10.15.4 (latest)
MacBook Air 2017
Affinity Designer 1.8.3 (bug comes from 1.8v)
Screen_Recording_2020-04-20_at_15_03_20.mov