As a 1MM on UA (including CO) I had a connection on same aircraft once that I recall, pre-COVID, with different flight numbers IAH-IAD-PVD; different crew also. The same flight # change of gauge flights actually annoy me, but that is for a different discussion I guess, but I had several of those IAH-EWR-Europe once years past. I believe the Mongolia flights are technically IAH origin now via Tokyo.

I did have a ticket bought for me once with one of those odd but sometimes offered out station connections on UA where it was IAH-TYS-EWR and a return EWR-SDF-IAH. A yahoo at one of my civilian companies picked that option just to be goofy, but I had fun with it. They made me get off both ways and reboard, but as a GS at the time it was no big deal other than extra time.

I have done some one day turns both in Europe and Guam and had the same crew back. Happened to me on a one night turn out of FRA and AMS to IAH about 8-9 years ago, and GUM in 2019.

Now with AA, when they had the GSA pair contract on IAH-COS, I regularly had to miss the UA non-stop and fly AA via DFW and that was a same plane, crew, and flight number. Several of us through pax were always on-board and given the option to stay on board or get off, but if one got off they had to wait and board with the new pax. Once Gene Krantz was on our IAH-(DFW)-COS flight and all of us Air Force folk had a brief but really cool chat with him, but I digress.