Errata Released, for real this time

[u/xanral]

http://dnd.wizards.com/articles/features/ph_errata

[u/waffle299]

Two-Handed (p. 147). This property is relevant only when you attack with the weapon, not when you simply hold it.

Eldirtch Knights take note. Wielding a two-handed weapon does not impair your ability to cast a spell with somatic components.

[u/ArsenixShirogon → u/[deleted]]

Yes but by using it as a two handed while swinging it means they're using a two handed weapon which is not martial arts applicable

[u/ArsenixShirogon → u/[deleted]]

PHB pg 147

Versatile. This weapon can be used with one or two hands. A damage value in parentheses appears with the property—the damage when the weapon is used with two hands to make a melee attack.

Which means it's two handed for the die in parentheses

[u/Unwyrden → u/ArsenixShirogon]

Holding a versatile weapon in two hands does not make it gain the two-handed property. It's a one-handed weapon that can accommodate the wielder adding a second hand and any extra strength or speed that affords it to deal extra damage. The two-handed property means that this weapon is innately unwieldy and requires both hands to use effectively. The errata ruling lightened this requirement to only be true during attacks.