I think I figured out what was happening, your MP4 file contained metadata embedded in it, MCEBuddy was overwriting it with the metadata from your filename (which was causing the extra . in it).
I’ve fixed it by providing a separate option in the metadata correction page to overwrite the metadata using the filename metadata (which conforms to the standard you referred to) and also an option for users to select if they want to overwrite the metadata using a specific internet provider. Metadata matching, extraction, renaming from files and downloading from the Internet
Please update to the latest 2.4.11 BETA build and it should fix your metadata issues.
Coming to the language, audio languages cannot be modified and is preserved based on the original file. Subtitle languages are set based on the original track or if unavailable, then the system language.