I got the same problem with fullcharged Nanoarmor insantvanishing on damage for Forge 1.4.0.64 (i think the Server where this happened has 1.4.0.59 like you too). Edit: The full armor was disappearing.
Thus, does it happen on any damage, large damage or nanosabre damage?
Everything that can damage Armor directly (Players, Arrows, Mobs).
Display MoreHave tested:
Poison
Falling
Fire
Arrows
Sword (PC and NPC)
and inactive nano-sword
All of the above just tick away at armor active Nano-Sword is the only thing that i can replicate it with.
Poison -> effectbaseddamage, not armordamage.
Falling -> fallingdamage, not armordamage.
Fire -> firedamage, not armordamage.
Arrows/Sword/Inactive Nanosword -> try more hits, maybe that help to replicate it.
Explosion -> Armordamage (maybe that Creeper caused my Armor to vanish, while fighting)
People on my server are reporting the same problem.
We run the same software as above.
All nano armor dissapears when hit with a nano saber. It doesn't dissapear when hit with other things.
The Sabers behavior on nano armor is intended according to the wiki. (lists as feature: able to destroy nano armor on players)
I don't know though whether or not it is supposed to be after the first hit. 
electric items are broken, wiki is griefed.
nanosaber deal HURGE amount of damage to any electric item, this allow to disable nanosuit in few hits but shoud not destroy any items.
nanosaber deal HURGE amount of damage to any electric item, this allow to disable nanosuit in few hits but shoud not destroy any items.
I remember to have given NanoSabers the ability to DESTROY Nano&Quantum Suits. though i agree, it definitely shouldn't onehit a Nanosuit, probably a numerical oversight.
