I noticed something similiar / maybe the same from another angle yesterday, while going over making sure all the brainkeys were correctly written down in my archives.
The archive matches the seed displayed by inputting the correct password in the wallet, however I cannot verify the brainkey, the button never becomes clickable, like it's still missing words.
I tried copy-pasting and just to be sure, also writing the words manually after visually comparing them (several times). It didn't work.