Turns out that the Astrons were not blowing due to anything with the soft-start. Also, we had a theory about electro-magnetic interference... wrong.
Rather, a bunch of PSUs made in April 2010 had an under-voltage capacitor inside (serial numbers 2010030xxx) and Astron admits that their testing regime would not find it. A 5+ minute burn-in under load would have caused the cap to fail and blow the fuse if not the entire unit (which occurred for 3 of our customers).
We only lost one amp during an Astron failure, and we're repairing it. The Astrons in the field have already been recalled and we're currently replacing with JTs. I guess we're not the only ones seeing a speed-bump or two this month!