Found this out the hard way.
A disc space availability check is required before attempting to write a newly set password to the password database atleast via the “save new password” pop up when setting up new accounts or whatnot.
even though the write operation can’t proceed on a fully saturated disc and this isn’t braves’ problem obviously but brave will still try to write the new pass and breaks the link to the db cryptographically.
All passwords gone 
Idiot proofing needed.