Bulk edit changes more fields than what was indicated.

Situation:
3 "Select list" custom fields exist for a project. They have the same default value (=Not Applicable).

Action:
Bulk edit was selected to change 1 custom field to its default value.

Result:
For the selected issues all the custom fields values have been put to there default value.
The confirmation window showed however that only 1 custom field would be adjusted.