Hi,
The canvas turns into black some times (Especially when zoom in + pan). When I zoom out, it becomes normal. Kindly have a look at the screenshot. And, I couldn't regenerate this issue. It sometimes happens (not frequently).
Note: I have all my drivers updated to the latest version.
Version: Affinity Designer 1.7.3.481
Operating System : Windows 10 Pro
CPU : Intel i3-4005U with Intel HD 4400 Graphics
GPU: NVIDIA 820m 2GB
Tablet : One by Wacom (CTL-471)