We deploy to 6 different models of machines across our network, one 2013 business model manufactured by HP and the other 5 are Shuttle XPC models from years 2008-2012 (a little old, I agree), but the issue has occured with each model, so the hardware appears to be irrelevant.
We're using WinPE 5.0 for remote booting. We have a GPO that installs DA 6.9 upon the startup of a machine if it doesn't already have it, and then we install the automation partition on the machine that needs a task executed on it. It seems after that, a couple problems arise. The first one, which I have seen others post about as well, is the agent update showing a 'Brokered request at (time)' status. This eventually resolves itself within a day or two. Then next issue occurs at random, or so it seems. A job will be scheduled on a machine either at a later time or immediately via drag-and-drop, and some start when they are supposed to while others show a blank status until the job is deleted.
We have machines dispersed across 24 subnets and a VLAN on each switch designated for the machines only. Our network uses DHCP for the machine IPs, but GSS uses MAC addresses to stay connected to the machines that are pointed to the server, so I don't believe IP addressing is relevant either.
Let me know what else I need to specify; I've just recently started using the product, so I'm not sure what else comes into play.