Search Results can disappear depending on the permissions of a user, but the count still shows the correct number.
Search Results can disappear when there is a document linked in multiple projects in the results but the results disappearing depends on the permissions of the user in those projects and also if the search is run for the first time.
If there is no linked document in the search results, the problem does not occur.
If the user has permissions to all projects of a linked document, the problem does not occur (which means that the problem never occurs for admins).
When adding a user to multiple groups, it affects the visibility of the saved search documents in the project because the permissions of the user is changed in some of the projects to which the document is linked.
Once the problem occurs none (or almost none) of the search results are shown but the count at the bottom still shows the correct number of documents that should be shown (but are not). No errors are shown.
The issue is most likely to occur from the second time onwards. When running the search for the first time the correct results are shown, the second time that search results should show the same documents, but it doesn’t show. Note that this symptom is not always there.