User ID is a flow field. Cross-column search is not supported on flow fields. Currently, we don't have a context that the user is searching specifically in this field to show any meaningful message.

As a workaround can be used: Use the advanced filtering page to filter on the "User ID" column for a value like *searchTerm* (the * allow partial matching of a value, e.g. search for "test" will match even in ATESTB),

, but it will be very helpful if we improve this behavior in one of our future releases.