I have seen this behavior as well. It seems to me that it loads up all managed Macs first, then displays only the ones that are added to the Static Group. I can tell this because for a brief moment before it comes to the page with the Done, History, Clone, View and etc. buttons, I can see it looking like its about to load all known Mac inventory (You can see all the display columns appear with the chasing bars loading icon below it for a second or two). I have no idea why it does this though. Why does it need to pull up every managed device just to look at the few that are in the group? It seems to me that the JSS should only load all systems if one clicks on the Edit button for that group, because, presumably at that point, you NEED to see all devices in order to make changes to the group. Not if I'm simply pulling up the group to view its existing contents.
To add insult to injury, at least with our JSS, if I do click Edit on that group, guess what happens? Yes, the JSS RE-loads all managed devices. IOW, what it JUST did before viewing the group it ends up repeating, which seems doubly pointless. Talk about hitting your JSS needlessly.
It seems like what's needed here to correct this behavior is to have the buttons that let you Edit, Clone and other actions also show on the page that simply displays the machines in the group. Right now, those functions are absent on that page, so you can't take any editing actions from that view. You need to go back to the previous view, which ends up loading all the devices first.
For the time being, switching out the URL to the specific view one is at least a temporary workaround. I would like to see Jamf improve this behavior though. Its pretty wasteful of cycles to need to sit and wait for all devices to be read in, just to view the existing membership.
