The first thing I'm going to say is I absolutely hate Rayman Revolution; not just because of the game in general, but because of what a buggy mess it is. I encounter countless glitches every time I play it, in fact today I had to reset the game three times in one sitting due to the game glitching out in some way or simply crashing.
First off there's the one that everyone knows; the sound effect loop glitch that usually occurs with the helicopter sound effect, where it will start playing continuously and keep overlapping until the next loading screen, where it will be stopped by a random sound effect (that is if it doesn't crash the game first).
There are two cutscene glitches I encountered today, the first was, if I remember correctly, at the emd of "Beneath the Lava Sanctuary, once you free the Teensie at the end, a mini cutscene will play, and what happened today was when I freed the Teensie, some of those black furball things were still coming after me, they floated around Rayman during the cutscene, before disappearing halfway through, which I suppose is nothing out of the ordinary, but then as the mini cutscene was supposed to end as the Teensie walked off, the black dialogue bar stayed there at the bottom of the screen and Rayman was just stood there, I couldn't move and the only movement happening on-screen was Rayman's idle animation, along with the occasional random camera shift. I couldn't even pause the game, forcing me to reset my PS2.
Another thing that happened was after one of the Razorbeard cutscenes was over, the game continued as normal until the infamous helicopter sound effect glitch occured, so I reloaded the save file and the cutscene played in fast motion, everything but the sound was running faster than it should; of course, the dialogue couldn't keep up and the voices kept stopping or just overlapping eachother, I have no idea why that happened.
Also, the last glitch I encountered was during the final boss, where after dying once, the music for the first phase wasn't playing.