I'm using that sword and I've noticed two things: apparently this weapon has fixed 100% chance to hit as I go with Hectic speed aiming at the head and didn't miss a single time so far,alas,I also can't deal critical strikes (1 crit after clearing 2 areas so far,crit stat is at 10). Neither of those are mentioned in the item description. Is it a bug,or it's intentional? Does anyone know?

Tried it, the same with me.
Meh, wish I did not read your explanation. Now whenever I'll be in a tight spot, I'll be inclined to resort to this "easy way out" which is outright cheating.