HELP. blew rc receiver (with pics)

Hey. Know I posted something similar but after that post I’m not sure why it blew. All was working fine, moved everything over to another board, plugged cables from the esc to the receiver and Boom. Loud bang. Their is visible damage on the receiver. NOTHING was changed when switching decks

SETUP 2x 3s 5200mah multistar lipo 10c Hobbyking 120a ubec boat esc Rockstaa 2 in 1 set Aliendrivesystem motor and drive kit Used 12awg turnigy wires for series connector etc