Ok, got this email from Zendesk in response to my flagging this as a potential bug:
Thanks for bringing this matter to our attention. This issue has been tracked in our internal bug tracker and we’re currently investigating. In the meantime we recommend doing the following:
• Launch Microsoft Flight Simulator
• Go to Options > General
• Select Graphics
• Under Advanced Settings and scale down “Render Scaling” to 80 instead of 100 or above.