Comment 5 for bug 1755322

Thx. So, the keyslot 2 was not converted, but added later once device was already in luks2 mode.

Anyway, all offsets and parameters look correct, I was able to recreate the same sized device and it works for me (with upstream git, 2.0.2+).

Can you try from command line for each slot and passphrases:
 cryptsetup luksOpen <device> --test-passphrase -T 1 -v

If anything is not accepted (and you are sure the passphrase is correct:), please add --debug keyword and paste output here.

Otherwise it is something special to Ubuntu that someone else have to analyse :-)