Working on a blog index with no preview open I jumped to Safari to look up a topic in Sparkle community (how to create a return to blog index button) and in the background Sparkle crashed giving a crash report.
Restarted and it did it again. Not deterred I started it again and its running OK for the moment
Running: iMac 27" Catalina 10.17.7 with Sparkle 4.2 (16700) crash report available if wanted