In the classic condition designer, a question whose condition (relevance) is '1' - the default of new questions - shows the note 'Note: This question uses a customized condition. If you create a condition using this editor the current customized condition will be overwritten.' instead of 'This question is always shown.'

Cause: application/models/services/SurveyCondition.php line 1608:
} elseif (!empty(trim((string) $oQuestion->relevance)) || trim((string) $oQuestion->relevance) == '1') {
The second part makes '1' count as a customized condition; it should exclude '1' (e.g. && trim(...) !== '1').