2012 TDI Jetta wagon drops into neutral.

My 2012 Jetta sometimes acts like it went into neutral. Shifter still says it’s in drive. The lost traction light will also come on. The only way to correct this is to coast to a stop and the shut down the engine and restart. The car then drives great for a while but this keeps happening. The panoramic sunroof drains were clogged and had standing water on the floor. I heard it could be the transmission module. Is there anyway to test this or does anyone have any other idea the cause of my problem? I did get the drains unclogged.
When I bought the car it did come with a power train warranty. Does anybody think this would be covered?