I think I Found a bug using PW Flex/Mini shooting at HSS...

UPDATE:

Both of my 580EXII are NOT working properly anymore. My associate photog was a witness to this.

I was shooting at a wedding reception and had two of my 580EXIIs on light stands attached to the FlexTT5 via AC5 Soft Shield. The other 580EXII was standing freely on the FlexTT5 via Speedlite foot-stand with NO AC5.

All PocketWizards are using the latest beta firmware. All settings were o Default with exception of Second Curtain Sync set to 1/100 Second.

The flashes were firing perfectly at long distances (75 feet or more) for at least 15 to 20 mins. Then later on my shots were suddenly dark. I can see the Speedlites firing but everything ended up being underexposed.

I turned off the 580EXIIs (attached to AC5) and placed it on my Canon 5D MKII camera (via MiniTT1) and tried firing off a few shots. It flashed but still underexposed. Turned everything off and then took the MiniTT1 off. the 580EXII still didn't work. Same thing happened to my previous post. ETTL only preflashed....and at Manual setting at 1/128 power, flash popped off extremely bright.

The other 580EXII without the AC5 still works.

I guess I'll stay away from the 580EXII and use my 430EXIIs instead or forgo the use of the AC5 Soft Shields..

I had both my 580EXIIs fail on the same job about a month ago.
They were on AC5 filters with the shield in place.
Sent them to Canon, both required new battery cages and some other work.
Got them back, one worked fine, the other worked for about 5 test shots then failed again.
Sent it back and they replaced a circuit board.
Both of them are working fine now but I use them on a MiniTT1 on camera and use my 580EXs on the TT5s.
No problems with the 580EXs on the TT5s with filter and shield.

The failure with the 580EXIIs was the flash not firing for exposure just for the pre-flash.

In addition to the electrical noise, I think there is a weakness in the circuitry in the 580EXIIs. Maybe the two are related.