So you are blaming Yuneec that you change the standard setup with put on some weight with a heavy filter? Those small motors that stear the gimbal is very sensitive and must not be congested. In My opinion it’s your own fault and not Yuneec:s.
It's normal to change filters in photography... Nothing has written about the filter, expect their size. If you cant use something, They should write about it. Now I know, It's only expensive toy, not professional device .