Are these agents pointing to a Distribution Server or the internet for their files?
Agent logs from the agent client would help, You may see errors in the STAgentUpdater.log when it attempts to update the WindowsPatchData.zip.
You will need to enable All logging in the Agent Policy to see helpful information, skip to 7 if it's already enabled.
1. Open the agent policy assigned to the machine you want to troubleshoot.
2. Change the logging level to ‘All’ and Save and update Agents. Choose to update agents if prompted.
3. Attempt to reproduce the issue.
4. Take a look in the STAgentUpdater.log and search for WindowsPatchData.zip and look for errors.