* Affinity Designer 1.5.4, MacBook Pro Mid 2014, Graphics Card: Intel Iris Pro 1536 MB
I used my MacBookPro with an external monitor (Mini Display Port connected). Then send Mac to sleep, and woke it up on HDMI connected Beamer for a demo.
Unfortunately, about the half of my loaded documents had a black canvas. The "Navigator" showed the right drawing. Only the canvas is black. A can even "Command+A" select all objects, what gives them a blue outline. But still the canvas is black.
Zoom pan did not help. Only thing that helped was closing and reopening all the black images.
Fun fact: some loaded images had no problem at all and survived the suspend/resume and monitor change without problems.
As I said: about half the loaded images went black...
See attachment! PAy attention to the navigator on the bottom right.