Hi Scott,
With my Digitrax system similar to yours (just older), I ran up to six dual-motor Atlas and MTH locos in the same power districts with no issues. I had the track power set to "HO" - about 15V and used 8A boosters. The power districts were subdivided with PSXs and one PSX-AR for an auto-reversing section.
These "China-drive" locos typically draw less then 1 Amp each pulling up to 20 x 1lb cars on level track. So I'd be surprised if the issue is current draw or track Voltage. I actually use HO decoders in them now on my ESU CabControl system with no issues.
So I would be looking at the auto-reversing setup for the issues first. Can you give us a simple diagram of the setup? That may help. For example, if a long train can span the entire A-R section that could be an issue. If two trains can cross the A-R section gaps at the same time that could also. If the A-R section is next to different booster districts at each end, or to more AR-1s, so could that. If the boosters have a faster reaction time than the AR-1 that's another factor. And if you have Frog Juicers or similar they can also be a factor.
There's a reaction time hierarchy to short circuits (over-current) to make it all work. Devices inside a power district need to be fastest e.g Frog juicers. Then auto reversers and power district devices e.g. AR-1, PSX, PSX-AR, and the slowest reaction time needs to be at the booster.
The AR-1 is an old design these days and not the fastest. So you likely need to set your boosters to slower reaction time.
One last thing to look at: With Digitrax you must have a large booster common wire e.g. 14GA between each booster and the command station/booster connections. Do not connect this wire to house ground though! This ensures sufficient current can flow at a short circuit to trigger these devices. Without it, the only path for this current is through the tiny Loconet wires.
HTH