Dene
Premium Member
No. This can happen during scrambling too. I've had it a few times in competition on loose cubes. It results in an extra attempt.
In this case, without any proof that the corner was twisted during solving (how could you possibly prove that after the solve?), the decision I make as delegate is to blame the competitor for using such a loose cube, and I DNF the solve if they left the corner twisted (or go with the time the competitor got if they fully solved it in the end).