Bah, I thought that dispute is something that has been going on since Battletech/mechwarriors inception. For some reason the Madcat/timberwolf comes to mind, in terms of claims of the design originally being a robotech one or something?
Ahh, the infamous unseen mechs.
This dispute has been going on for donkeys years. They just dropped the disputed mech designs (they were "phased out") and later they re-introduced them as re-designed updated models that did not infringe copyright any more.
The only problem is many of the disputed "unseen" mechs were pretty iconic designs like the warhammer, battlemaster, archer and marauder amongst others.
The mad cat was never an unseen.
Edit : Here you go
http://www.sarna.net/wiki/Unseen