i'm having game freezes (from 1 to 10 seconds) while having the nano saber activated. The game defreezes enough time so the nano saber does it's "activated" animation and then the game freezes again...
Strange thing is that i've been able to kill some mobs before any of this started to happen.
When i've managed to exit and enter the level again (no minecraft restart) the freezing issue still happens, but the animation is not playing (maybe it's not the animation? ). Exiting minecraft and entering again made the issue disappear, though.
When the issue starts it doesn't end until you exit the game, so maybe it's not nano saber related...