As stolen from the US forum (post by Talimah)
There is a frustrating interaction with the Anima Vacuum and druid’s Flight Form, this includes using it on at least quest 86595, 86606, 89242.
After using the item and channelling, flight form going forward has an offset between your camera and the actual pitch of your character. You are not able to fly in a straight line in either dragonriding or traditional flight modes, the broken offset remains until you mount/dismount a normal mount.
If you channel the item multiple items, problem gets even worse. After a few channels, flight-form dragonriding is unusable as it immediately violently pitches up.