Pages with Incomplete Missing Tags
The Missing Tags report has a nuance that shows pages which may have tags partially implemented. This helps pinpoint pages that have a specific tag on them but are not sending data to all the accounts they should, resulting in an incomplete tag implementation.
Incomplete tag implementations happen when more than one account is found for a tag during an audit but not every page is implemented with all the accounts. Every page doesn't necessarily need to send data to every account, but where you have multiple instances of a tag or multiple accounts on a page, you want to be able to easily see where the tags may not be implemented completely.
Pages with an incomplete set of tags show in the light shaded portion of the bar.

Clicking the tag shows that tag broken down by accounts.

The top line of the Missing Tags detail shows all the pages where the tag could not be found in the audit. Any line that exceeds the length of the top line indicates the number of pages missing the account for that line in addition to the pages where the tag was not found at all.