I've had plenty of experience with this issue, as I dealt with it for about a full season.
- Be sure to turn on your system before any of the 4PK guys do, if possible.
- If they're already on, back away from them (like 50 feet or around the corner and try turning your system on there). This is a pain... once I had to go outside the building in the middle of winter to get the system to lock in... fun.
- Once it locks in, it works fine throughout the race.

I finally broke down and bought a 2nd module, just so that I wouldn't be out of commission. BTW, the updated modules are designated by red marking on the circuit board by where the pins connect. Then I sent the 1st module in, and I'll have a spare when it comes back.