Just to double-check, what you did here is the following?
No, the first time I started up Brave Browser, I fully went into the browser’s newly created bare profile, then imported settings from my primary Mozilla Firefox profile. That process missed passwords… I came up with three ways it lost passwords… two of which were explained away as a non-issue, the third set is the troubling set.
I would think this qualifies as a bug against Brave Browser’s Mozilla Firefox settings import / harvest capability.
Ok, so earlier you were trying to make it work by exporting a CSV file and then importing it in Brave, but in this last attempt you used the automatic import feature?
I was trying to figure out where passwords were coming up missing doing the Mozilla Firefox to Brave Browser settings migration… that is how I began exporting password CSV files, observing the password count dropping. I was surprised not to see the same number of passwords.