Mark Cuban's 'Shark Tank' Partner Defends Mavs Owner, 'No Problems Here'

... 'No Problems Here'

One of Mark Cuban's "Shark Tank" business partners says the billionaire always acted like a consummate pro with her ... and she'd be SHOCKED if he really did know about the horrible things happening with the Dallas Mavs.

We spoke with Raven Thomas who got Mark to invest in her gourmet food business -- The Painted Pretzel -- during a 2012 episode of "Shark Tank."

Thomas had nothing but positive things to say about her 6 year work relationship with Cuban -- and says he's always been a respectful partner and honorable business owner.

In fact, Thomas says she was "shocked" by the allegations that the Mavs front office was a nightmare for women ... saying, "I would be…