12:07 PM PT -- We've spoken to several employees at the Inglewood Park Cemetery who all tell us the same thing, Dre was never in the parking lot ... he pulled up on the street within the cemetery near his grandmother's gravesite.
The employees told us they never saw Dre get served while the casket was being lowered, so it's likely he was hit with the docs when he walked back to his car, about 50 yards away.
Dr. Dre's divorce has been extremely contentious, and something happened Monday that punctuates the bitterness ... a process server for his ex-wife attempted to serve him with legal docs at the cemetery where he buried his grandmother.
Sources with direct knowledge tell TMZ ... Dre was at a Los Angeles cemetery Monday to put the woman who helped raise him in her final resting place.
There's a dispute over where exactly Dre was confronted by the process server. Sources connected to Dre tell TMZ ... a process server came up to him at the burial site as Dre was standing by his grandma's casket and tried serving him. Sources connected to Nicole Young tell TMZ ... Dre was served in the cemetery's parking lot after the burial.
Either way ... we're told Dre recoiled in anger and wouldn't take the documents in hand. Our Dre sources claim the process server dropped the documents by the gravesite. Our Nicole sources say they were dropped in the parking lot.
The papers involved payment of Nicole's attorney's fees. There's a dispute over how much he was supposed to pay. The music mogul paid $325,433. The judge signed an order that he owed a total of $1,550,000. Dre believes that amount is in error and he paid the full fee. Nicole says the order is clear ... Dre owes a balance of $1,224,567. The legal docs that were served included the judge's final order of $1,550,000.
Either way ... this divorce is about as acrimonious as it gets.