That’s because the metadata is being taken from your mp4 file and your mp4 file doesn’t have any subtitle or season or episode number.
2018-05-21T08:46:18 MCEBuddy.MetaData.VideoMetaData → Extracted Generic Tags: Title: NOVA
SubTitle:
Description: Discover how a world of microbes living in and on you can make you sick.
Season: 0
Episode: 0
It only has a Title and Description. MCEBuddy needs atleast two items to match the metadata on against tvdb/imdb.
Title
AND
Subtitle or Season/Episode or Original Broadcast Date
Without the second piece of information it has not idea what episode it’s trying to look for so you end up with your default 99.
See this: