Yes, her foot was off the floor twice. It was still the best dance of the night, and the best viennese walz of the series.
Actually, the foot off the floor was not actually Kara's fault, but Artem's. Artem lifted her just a fraction further up than he should, so her foot bounced off the floor. It is an easy mistake to make, even for a proffessional. This is a very difficult move, that requires a hell of a lot of precision, so credit to them for risking it.
So, OP, before you name tag someone, do us a favour and do your homework first.