Here on macOS 10.14 with Cubase Pro 10.0.10 it resets to C3. I thought it might just reset to the nearest C, but here it resets to C3. Highly annoying. Makes Padshop Pro unusable right now.
Update:
• trying to go back to Cubase 9.5.41 makes unfortunately no difference. The version of PadShop installed by Cubase 10 must be the culprit here. I had only Cubase 9.5.41 on this rig without this issue.
Update 2:
• testing this in a completely empty new project, it also resets to C4 on my Mac here.