@Redistro, Thanks for posting in Q&A. From your description, I know some devices are showing pending for 4 days when deploy windows update ring policy.
For these devices, I suggest try restarting the devices to see if the status will be changed.
Meanwhile, go to one affected device and view configured update policies, then verify that the policy type is Mobile Device Management. Verify the registry key under HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\PolicyManager\current\device\Update to see our setting related registry key is properly configured. Here is a link with detailed troubleshooting steps for your reference:
Please try the above suggestion and if there's any update, feel free to let us know.
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