I tested this out for a stam sorc set up and the morph Ball of Lightning of Bolt Escape cancels Rapid Maneuver.
It was done without any mobs around me or players, just in the open field.
(PC NA)
-Saulo Stamina Sorcerer
-skillastat Stamina Nightblade
-a blade spirit Stamina Templar
-Ultima Online I Magicka Dragonknight
-'Solo DC* Stamina Sorcerer
-'Ultima Online Stamina Dragonknight
-Nerd Dk Tank Dragonknight
-Solochi Magicka Sorcerer
-Solo Lucci Magicka Nightblade
-Sølomon Magicka Warden
*All characters are EP, except for one DC.
French Canadian!