Have several computers not connected for 30 days or more but check-in on Jamf Pro is normal

I ran into the same issue this week and it was caused by a stuck EA Script. The inventory policy log shows the inventory being collected up to that extension attribute then it stops, and eventually times out and fails. What do your logs say for your inventory update policy?

Same issue here with just one pc (so far). Any news on this?

Issue resolved itself after user restarted, but I did get this response from support 

We have seen at times if a machine gets a build up of Threat Feed Events this can impact communication. On some of these machine open terminal and run the below command. sudo protectctl info -v

A couple things to check for in this output. In the 'Monitors' section look at 'Threat Feed'. Under the 'Events' column if this is a very large number, example would be in the 10s or 100s of thousands, we'll want to reboot the machine. This should clear the Events. Before rebooting look at the 'Uptime'. We do see these Events build up if the machine hasn't rebooted in a while.

I can confirm the reboot works. I had 2 and one of them did reboot the machine and it was gone. Still need to convince the other to restart it. Programmers can be a bit difficult with when it comes to rebooting their machines...