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Apologies for the delayed response. Here are some pointers that should help you with the reported scenario.
Some of the common reasons of such observation are documented here, especially the subsections highlighted below.
- Update does not show available for machine
- Windows Defender update shows missing
- Superseded updates indicated as missing
Also, please review if there is an exception message below machines indicating a HRESULT or status. In case the troubleshooting docs above does not help you, please check if you have configured WSUS or SCCM, as the behavior might be different depending on the updates approved for these channels. Please refer to this link for more details.
Please let me know if you have any questions.
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