A competitor used a cube with a logo in his Multi-Blind attempt. This was only found after the attempt.
Currently, according to 3k2, using a non-permitted puzzle results in DNF of the attempt. As this would be a very harsh consequence in Multi-Blind, the WRC has decided count the non-permitted puzzle as unsolved, without affecting other puzzles
The WRC is discussing how to revise the Regulations to reflect this policy (see GitHub issue).