As of the latest update, there seems to be a hitbox issue causing one of the hits of Sandman’s sp2 to whiff, giving the opponent the chance to block the rest of the special. It’s specifically the hit wherein he rises up from the ground, shown here:

However, it also seems like this is a champ-specific issue and the attack connects fine against some champs. I first noticed this issue against Mr. Sinister as shown in the above image, but when I went to recreate it in practice mode for this post I fought against Destroyer for no particular reason and could not replicate the issue.

As shown in the first image though the issue definitely exists, so either it’s an inconsistent bug or it’s an issue with the hitboxes against specific champs.