Good counter examples. Etymonline will break roots down for you.

https://www.etymonline.com/word/unbalanced#etymonline_v_2490...

Like most things in linguistics, the 'rules' are more a rule of thumb than the mathimatical sort.

Germanic pre/post fixes seem like they stick to pre-inkhorn roots better.

https://en.wikipedia.org/wiki/Inkhorn_term