Aimp not sorting some tracks by track number

[loekatje]

Hi,
Up until very recently aimp sorted the songs in albums by their track number, then for like 7 albums it sorted the songs alphabetically and then started sorting them by track number again out of nowhere. (Pictures attached).
I've checked the metadata just in case and it's fine (the same field properly filled with the track number).
Any tips are welcome.
Cheers!

[Artem]

The entries sorts according the sorting parameters defined by the columns: