Quoted from Betelgeuse:
BSD has an issue where your bonus is lost if you get a tilt warning during a ball drain... which is when you would most often expect a tilt warning to occur.
So does Doctor Who.
Both have been fixed. There's also a setting on BSD to make the mystery just be worth 500k for tournament usage.
I *really* wish the forum that used to host this information was still around! In 2012-2013, no one in the mainstream pinside arena was interested in this stuff. No idea why pinhacks disappeared, but there was tons of information there and fixes/patches for this stuff. It went members-only, then one day, was just gone.
From what I recall from the thread there, the tilt bug is because Bill Pfutzenreuter the programmer of both games liked to roll his own routines instead of using the built-in ones, for whatever reason, and it's just a bug that slipped by.
Here is the wayback machine link for the site, for some reason I always forget to look here for sites.... I'll have to re-read a lot of the stuff there to see if the tilt warning stuff is covered I know there were 2 ways to patch it.
Oh, and in no way is this archive applicable to whatever Soren's cooking up now - probably doesn't belong in this thread, but a lot of the same issues with games have cropped up over the years and information there might help him/others in formulating their own fixes.
EDIT: Looks like the wayback machine didn't capture all the actual messages just the headers. Bummer but you can see what was being looked at in the past at least!