GPS loss after several minutes of flight

So I have been battling this for the last 2 weeks. After 2-5 minutes of flight GPS HDOP climbs rapidly and NSATS falls, sometimes to zero. The Pixhawk, GPS, and Telemetry modules + all cables have all been replaced and the exact same symptoms persist. Actual GPS reception is good during the event, I had my small Garmin sitting on the table and it experienced no such loss of signal. On one flight, I lost GPS @ 2 minutes or so. EKF refused to go back to POS HOLD but after the loss and recovery of signal, the remaining 45 minutes of flight had no GPS issues. I am at a loss. After dozens of builds and hundreds of flight hours I have gotten to a problem that I cannot solve through research or isolate through testing. Any input is welcome.

44 inch c-c quad
27.5" props
12S flight battery
APM:Copter 3.3.2 … sp=sharing

Did you check wiring on the gps module side? I had issue with gps sometimes and found one of the wires soldered to the module was coming loose.