When importing via the device scanner (for tv) the special or Season 00 episodes are imported fine ... however when updating via the internet the scanner adds new entries and doesn't recognise what is there so you end up with double ...
i.e. a tv show has 3 seasons ... seasons 01 and 02 and season 00 (specials) the scanner will import data into seasons 01 and 02 but will add new entries for season 00 ... if you had 3 specials originally you end up with 6 (3 for original scanned files and 3 for web import info)
That's one of the best problem descriptions I've seen in a long time, very complete. On the web imported versions, what distinguishes those records from the ones you have (ie are the season/episode numbers the same? Do both sets of records contain the same data from the web? Are you getting web information from multiple sites?
Getting the info from one site ... only happens with the specials ... all other seasons update fine:-
The following shows the db after doing a web update ... see how it doubles up the episodes ... the top one is the device scanner import (filesize etc) and the second one is the web import (episode info etc)
The following image is of my episode info in the edit window ... the web update has ignored the originals and created new entries instead of updating what is there as it does with the S01, S02 etc