Just to make sure that those machines are really, really gone, let's check in a few places:
When you click the Jamf logo in the top left, total inventory counts should be displayed on the left.
Under Computers > Search Inventory, if you execute a search with nothing in the search bar, you should get your entire inventory.
Using an API call:
#!/bin/bash
API_USER=""
API_PASS=""
JSS_URL=""
CREDENTIALS=$(printf "${API_USER}:${API_PASS}" | iconv -t ISO-8859-1 | base64 -i -)
curl -X GET -s -H "Authorization: Basic $CREDENTIALS" "${JSS_URL}/JSSResource/computers" -H "accept: application/xml"
exit 0
This API call should spit out your entire device inventory, but just the ID and name. Fill in your username, password, and JSS URL, and it should respond with an XML list of your entire inventory.
If none of these are reporting any inventory past the 2 you mentioned, you might have an issue with sites. Next to your profile picture in the top bar, there's a site selection dropdown. Make sure its set to Full Jamf Pro, or whichever site has your entire inventory. If that dropdown doesn't exist, sites are not enabled and that's not your issue.
The last thing I would look at is: do the other Macs even check in anymore? If the Macs that are no longer listed are still able to run Jamf recon and Jamf checkJSSConnection without issues, then their inventory records are still in the JSS somewhere, but I'm not sure where to look for them at that point.
If none of these steps are reporting the expected inventory, it's looking more and more like those records are missing from the SQL db entirely. That's probably when forum support ends and a ticket should be opened with Jamf Support.
That's everything that I can think of, best of luck finding those records!
