Mike --

The ACP.EXE program hasn't changed in any of the hot fixes, so the hubbing code has been the same since beforfe Hot Fix 1. The only changes in the hotfixes are in the scripts which implement the observing logic, the web pages, etc. With that said, it is certainly possible that those changes in observing logic could have changed the timing of requests to the driver such that a timing hole in the driver/controller has been exposed. ACP's use of the driver is pretty "busy" and it's common that it is the thing that exposes weaknesses.

Are you involved in the official AP driver beta program? If not, you might want to contact AP and get on it. I think they are close to release though and you might want to wait for that.