SSM seems to of possibly gotten a little creative in their height listings this year. They also gave Katchouk a similar height boost who was measured at 6'125 at the combine and is now listed at 6'3, about 3 months later. While in Senyshyn's case his combine was over a year ago, he measured in at 6'1 there.
Yeah I seriously question that he's 6'3, maybe with skates on.