The only one I know about is the Daisley and Kerslake issue with Blizzard and Diary that went to court and got dropped because they were enlisted as studio musicians and were never under contract to receive royalties. Sharon, vicious thing she is, had those two albums re-recorded with a new bassist and drummer as a great big Eff You to both those guys, which she got sued for. Other than that, I’ve never heard anything about musicians getting screwed by Ozzy or Sharon. She sure as heck flew some lawsuits, but they were usually to protect his brand and business. She makes pit-bulls look like poodles. Scary woman.
The music business can be very vicious.