Sounds like you've had more of a response than I've received. They weren't aware of the issue and neither was VMware (they basically closed my ticket(s) and pointed the finger at HP). Interesting that they're saying it's a fault within ESXi itself, as so far it's been looking like a 100% HP issue.
To avoid the reboots, stop the hp-ams service after your host boots up and before the problem occurs. With that service stopped, the issue will not present itself. If your hosts don't have the ESXi shell enabled, and this bug occurs, then your only course of action is a reboot. If your ESXi shell is enabled (prior to the issue, as it can't spawn after the issue starts), you can still get in via console and stop the hp-ams service and recover your host without requiring a reboot.
On my servers it seems to occur randomly after 14 days. Some servers hit it almost immediately after two weeks, others were a bit later. You can see when the problem starts, as you'll notice issues start to get logged to /var/log/hpHelper.log similar to the following every 10 minutes or so:
AgentX master agent failed to respond to ping. Attempting to re-register.
ilo_close fd 8. data=0x49d6bd08
Failed: go_bye() read() returned err=1
As well as errors from cron not being able to spawn new processes, etc.
Cheers
-Joshua
