I noticed that the time will change by about 2 minutes 30 seconds. Perhaps I believe that resetting the data once achieved is the cause.

It occurred at "The survivor"

I'm probably going to take some more time tomorrow to do more investigating regarding the cutscene manipulation, since not knowing how it works really isn't beneficial for anyone (regardless of whether it's decided it will be allowed or not).

Right now I can confirm that off of a new file, Monk gets the short cutscene and Survivor gets the long one. Meeting 5P with one or the other previously on that save doesn't seem to be a factor. I'm not sure if the Hunter's data has any effect, but after I have him set up I'll post the save so anyone else who wants to test can quickly get started.

I'm suspecting that it may turn out to be a factor of restarting with an ascended slugcat, but we'll see.

I tested this myself & it requires a meeting with 5P as hunter. I did this on a clean file (manually deleted from the saves folder). First I unlocked hunter by ascending as a survivor, then got hunter to 5P and saved. As soon as I did this, I got the short cutscene as survivor. You don't even have to play monk, and you don't have to finish your game as hunter. Not sure if you even need to ascend as survivor (for instance, if you edit the save file to have unlock red, I haven't tried this and probably wont lol)