Weird phenomenon with TMNT IV SNES rom

[wyze2099]

Okay, so I have an SNES emulator with a "Turtles in Time" rom, and I just enjoy the heck out of it. It's a great game, and a great conversion of that game. But lately, I've noticed something really strange...

The emulator has the ability to record a gameplay movie in either .smv or .avi format, but most recently I decided to record my gameplay of my favorite level in TMNT IV, "Bury My Shell at Wounded Knee". I think it's a fun, fast-paced level that has yet to get old, even though I've placed a saved state at the beginning of the level so I can play it over and over.

But twice now, when I've reached Leatherhead as Donatello and kicked his butt, I've replayed the movie. Everything in the movie happened exactly the way I'd played it (obviously) ... except for halways through the fight with Leatherhead. Suddenly Donatello stops fighting intelligently and lets himself get whaled on over and over until he gets a game over. And that's not how I played it!

That's happened two different times now, and it's really perplexing, as it's never happened before (granted, I'd never tried to record that level before, either). Since when does a recording get to make up stuff? Has this happened to anyone else?