Rows without visits and unique users ("-") at the custom dimension reports

Hey there!
We’re tracking a portal with traffic ~ 5000 unique users/day.
Matomo (on-premise) is set up according to the manual https://matomo.org/faq/new-to-piwik/faq_137/. Rows limits set = 10,000. Matomo: 4.5.0, 10.2.41-MariaDB, PHP: 7.4.26.
We send logins of authorized users to Matomo as custom dimensions through dataLayer.
Observing the following problem: in the Logins report (Users-Logins), the table contains users with dashes (’-’) in Visits, Unique Users, Action etc on the last rows.


If I apply a segment for any of these logins for the same date in other reports, it has no activity.
The problem is observed when I choosing any period…
How does this data get into the report and how to avoid it?