Episodes without Aired date placed incorrectly when ordering list on Release date.
When a list of episodes is ordered on "Release date" the episodes without an "Aired" date are ordered as if they precede the episodes with an "Aired" date.
For example, when the list is ordered ascending, the episodes without an Aired date are placed before the episodes with an Aired date.
Please see my comment.
I think this is correct since a blank air date is basically 0, and would come first in a sorted list. Ideally the missing air date would be added on TVDB so that the data is corrected.