I tend to forget to stick things where they need to be, and having migrated from Open Office—prone to not inserting em dashes and smart quotes where I need them—I have memorized a goodly number of alt-inserts, the most important being the em-dash (—) and en-dash (–); these are represented on the keyboard by ALT+0151 and ALT+0150, respectively.
I botched a passage and, forgetting that Scrivener is smart enough to put them in the way that I need them, used the ALT+0151 for an em-dash.
Instead I got a “7.”
A second attempt got me a “/.”
The third time, still attempting the same command for an em-dash (ALT+0151): “Ï”
Still another attempt: “×.” (A multiplication/times symbol)
It seems to cycle between these four in a set order. It only does this when NUMLOCK is off, but…other programs handle the ALT+ insert without problems, regardless of the status of the NUMLOCK command.
Tested this in three projects, with the same results; restarted once to double-check. Tried it in Word, LibreOffice, Notepad, and WordPad as well, with no difficulties in any of those.