Found a really nasty incompatibility occurence. This character looks just fine as a PNG and SVG...
But when I try to open the exported SVG file with Affinity Designer (my current vector-graphic software), I get this:
I have no idea why this happens. The exported SVG file has everything, judging by both looking at the Layer window in Designer and viewing the SVG in a web browser (both Internet Explorer and Microsoft Edge). So this is a puzzling occurence (not to mention rather scary).