One of the tunes that is sometimes played played at Chassidic affairs during a debka/hora set is the crossover song, Mustapha. I assume it entered the repertoire via the Druse/Meron connection just like so many other melodies did. Naturally, it's now a holy nigun.
I haven't had this one called much lately on my sideman gigs, but thinking back to when it was, I remember that at club dates one of the sections is usually omitted. Check out Bob Azzam's version which has this "missing section". It's the last melodic section of the song in this version. (According to the "About This Video" information on the YouTube page, Azzam was Jewish.) This "missing piece" is also included on the Ken Gross arranged "Mostly Horas" recording of the song.
So what happened to this missing piece? Here's my theory. I suspect most musicians and bands were/are not aware of the original melody and learned it on the bandstand or just played it off of the sheet music they were given. There's a transcription of the tune on page 462 of "The Book", which is one of the unlicensed books floating around which was used by bandleaders to get through a club date years ago . That transcription omits this section. Since most weren't familiar with the song independently, and it wasn't being sung, the omission of a section passed unnoticed. So, I posit that it's all the result of a bad chart.
Similarly, you'll notice that there's a two bar vamp before each F minor section in Azzam's version. That vamp is also omitted from "The Book". That vamp is omitted on the Jewish bandstand in the States, even though it helps to set up the switch from major to minor nicely. I do have a recording of an Israeli clarinetist, Shmuel Ne'eman, on which he plays the two bar vamp before the first F minor section. He also plays the "missing section", but without a two bar vamp preceding it.
While we're on the subject, here's Dario Moreno's swinging version of the tune. Not to be confused with Queen's song "Mustapha".