I'm on Windows 1903 (18362.86), using Edge Insider Dev 188.8.131.52 (Bug 1 and 2 also appear on Edge Insider Canary 184.108.40.206, Bug 3 untested). I use a system-wide scale (not the one in Edge) at 150% (some bugs appear on 125% and 149% as well), and encountering bugs which seem related. All bugs don't appear on Chrome & old Edge using EdgeHTML. I confirmed they are not caused by extensions or other stuff.
@Deleted This is kind of similar to a bug that I reported. Edge Canary has difficulties with white text overlayed on top of a graphic. The problem can easily be duplicated on the Duolingo web site. I must increase the scale of the web page to 250% and 300% then scale it back to a more normal size for the pages to render properly.