Kathy Hilton Accuses Mauricio Umansky of Poaching Staff to Launch The Agency

Kathy Hilton's finally giving insight into her family's feud with Mauricio Umansky ... accusing Kyle Richards' estranged husband of shadiness when he left their family biz to launch his own.

The Hilton matriarch spilled it all during Wednesday's 'Real Housewives of Beverly Hills' reunion ... where she claimed her brother-in-law exited Hilton & Hyland -- her husband Rick Hilton's real estate biz -- with only a day's notice, and poached their staff too.

As Kathy put it, Rick had no problem with Mauricio leaving to do his own thing -- but only asked that he not take any employees with him ... a request she claims he ignored!

All was not hunky dory in the aftermath ... with Kathy even admitting that things were "funky" between herself and Kyle for some time.

It appears the Hilton family is far more willing to share their truth amid Kyle's separation from The Agency founder.

Remember, Paris Hilton came to her dad's defense after Mauricio attempted to paint a different picture about his fallout with the Hiltons in a teaser clip for Netflix's season 2 of "Buying Beverly Hills."

While Mauricio claimed he "got kind of f***ed by Hilton & Hyland" ... Paris hit back on Instagram Tuesday -- accusing her uncle of using her family's name to plug his reality TV career.

She torched him for going public with a private family matter, and added ... "It is enough already."

Despite her separation from Mauricio, Kyle still seems to be in her estranged hubby's corner. During the reunion, Kyle defended Mauricio for taking some Hilton & Hyland staffers when he bolted ... before shutting down the topic altogether.

The Hiltons might forgive, but they're not forgetting when it comes to Mauricio.