Same model same problem. I fixed mine once and it came loose again which is worse because after patching the floor I had to try and do the same spot again. I put in a 4" long 1/4-20 flat head bolt in place of the screw and put a wax nut on the bottom from under the trailer. That one won't come loose again. If they fix it under warranty make sure that they do it so it won't strip out again after you are out of warranty.
2018 Redwood 3901WB pulled by 2016 Chev 3500 HD DRW. Goodyear G114 tires, Moryde I.S., Kodiak Disc Brakes, Splendide W/D, Tire Minder TPMS, Sleep # King.