Blinkers and Hazzards

I went LED tail lights with LED front park/turn signals on my 71. I used the digital flashers for both hazard and turn signals. What I found was the polarity of the wires at both flasher units Was incorrect. I de pinned the connectors and swapped the wires and everything worked perfect. I can’t say that’s your issue with the incandescent in front and LED in rear but it’s a shot.