Who knew?! Jennifer Aniston's marriage got off to a cursed start when her pal Joel Silver's assistant DIED during the couple's honeymoon in Bora Bora!

Aniston and hubby Justin Theroux had a group honeymoon, with their best friends shacking up in luxury overwater bungalows at an exclusive French Polynesian hotel back in the summer of 2015 -- super-producer Joel Silver was one such guest. He brought along his assistant and his personal chef to the Four Seasons hotel -- Carmel Musgrove, 23, being his assistant/nanny.

Musgrove's family has filed a wrongful death lawsuit against Silver, his company and Silver's chef -- here's why ... Apparently Musgrove was at dinner with the group the night of Aug. 18 after day-drinking during a fishing trip. After dinner, she went back to the room of Silver's personal chef Martin Herold and continued drinking and doing drugs, according to the complaint. It is alleged that Herold provided cocaine to Musgrove. The last person to see her alive was a front desk receptionist who Musgrove asked for matches around midnight on the 18th. The next morning when Musgrove didn't turn up at breakfast, a search began and after more than a day of looking, her body was found on the banks of a nearby beach. An autopsy found her drowning to be the result of overconsumption of alcohol, consumption of cocaine, fatigue, and heat stroke.

Now Musgrove's family wants Silver to pay up ...