The gymnast demonstrating this combination bails over with a little arch to begin the inside endo, but then shows a good compression, and on the swing up and comes out of the skill with the correct hip roll-out action. On the pirouette to mixed grip he again has a slight arch that could be refined to a straighter position and keeps his head slightly out to maintain visual contact with the rail during his pirouette which helps him to regrasp the bar more consistently.
In general, one of the most common learning mistakes of either straddle or inside endo to full pirouette is to swing down crooked after the pirouette. The reason for this mistake is an excess of support transfer to the post arm. The gymnasts shift their weight like they were going to perform the regular front pirouette that they have learned before, and that really requires a support transfer beyond the vertical of the post arm to finish square in a different bar position.