After more time, it looks like it’s just a rare event where the Inform IDE gives the wrong first value for the ‘event’ type object. I used some code to ‘catch’ stray events and their values and there is only a single event happening (a hyperlink event) with a single value (1049). And it only happens if saying lists of 3 hyperlinks, not 4, which is fun.
I doubt very many people are reading this thread, but if anyone finds a crashing error with Bisquixe outside of the Inform IDE and outside of this buffer issue (Bisquixe problem with hyperlinks (input buffer message)), let me know so I can work more to track this down!
Zed helped me figure out a lot of these things.