I still think you and Don should get together and troubleshoot this yourselves. At least rule out hardware differences between your units... If they have identical components, you've ruled out that possibility.

Waiting for Ketron to do it for you (especially as you are not pressuring them with a warranty claim) might not work. If people aren't trying to get their money back, why would Ketron admit that the problem might be hardware related, if it will cost them a bundle to repair all those units with the fault? It's all well and good to rely on a company's honesty, but when fixing problems might put the company in serious financial straights, delay, obfuscate and deny are the usual responses, these days...

Trusting that an OS fix is going to solve the problem when there are things you could be doing yourself to find the issue is a bit optimistic. But I must say, I am still shocked that you don't at least play the Audya while you wait for what Ketron comes up with. It's obvious that Don has worked out a workflow that DOESN'T crash the unit, why not simply adopt his workflow until Ketron makes it possible to go back to yours?