Repeating string tags

[chrazer]

Apologies if this has been addressed already - I can't find anything about it on searching.
I've just bought a new SD card for my Sony Xperia and want to sync my entire library to it - it's around 19500 songs totalling 70GB or so. I'm doing it via phone rather than taking the SD card out to ensure the files convert (as they are various formats)
Most things sync without any problem but a few albums end up with increasingly long repeating tags. For example albums by Air will end up on my card with the artist as Air;Air;Air;Air etc. It doesn't really matter I guess as MM android still recognises them.
I've manually corrected the tags, cleared the tags and deleted then re-synced the files but it seems to happen with the same ones again and again. Am I missing something obvious. They display correctly in the library. I do use my custom fields for second, third, fourth etc artists but for these albums these fields are blank.

[Lowlander]

Which version of MMA, MMW and Android, and did you wifi or USB sync?

[chrazer]

I've just bought MM Gold 4.1.15.1830
Android is1.3.0.0683 - currently on the free version but likely to upgrade
I'm using mu USB-C cable
I wondered if it was to do with my using IDV3-2 tags? I'm trying with 3-1 insead

[Lowlander]

Try to Synchronize Tags on the affected files in MMW (Tools > Advanced Tag Management > Synchronize Tags). Remove the affected files from the device and then re-sync.