The following script app crashes SD 8.0 8A20 just by being open in SD. Once its window opens, a crash occurs anywhere from 2 to 45 seconds later with no user interaction involved. The runtime error is always the same: NSCFString characterAtIndex: Range or index out of bounds. The error started happening once I pasted in the final run handler at the end (ColonPathToFullColonPath). Initially I would lose the added text due to the crash (I always chose Crash instead of Continue), but I discovered that since the SD runtime exception could take up to a minute to happen, SD was still well enough to let me save it before the text was lost (which is why it now shows up at the end of the script). It’s as though SD is doing a delayed syntax scan when the crash occurs. My Mac is running in Dark mode and I am running an exact copy of Default Dark theme. (Setting the Default Dark theme fails to survive over a re-launch of the app; it always returns to Default Light. I found out that setting my own theme, even though an exact copy of Default Dark, enables proper Theme persistence.)
[At this point during posting I see no way to include a zip file of the app.]