I tested this in my old file, and to be sure I created a new file, and you can reproduce this consistently.
But the premise is a bit unclear, seems more reasons needs to be found.
untitled.epub
Use this, Ctrl select C and E, Or C and I, it will cause crash. But strangely E and I does not.
And I tried again, E and I crash too, but it didn't do that like 3 times. So I think the possibility mybe 90% the time?