To reproduce set your limit in the visitor log eg to 5 and then click on the next page. You will see in the Live model method when it fetches the data that it will be actually fetching 7 entries.
It does a
$limit + 1 here: https://github.com/matomo-org/matomo/blob/3.11.0/plugins/Live/Visualizations/VisitorLog.php#L57
and then another +1 here: https://github.com/matomo-org/matomo/blob/3.11.0/plugins/Live/Model.php#L43
This way you might skip in the end a visitor? Anyway, it should only do one of the plus ones. Probably the one in the visualisation can be simply removed.