Few things:

Modlog is different than seclog.

Accounts that were created before 2015 and were inactive, if they wake up suddenly and try to make password/email changes,those accounts get locked(its automated IIRC).

Global mods(or at least Hilariousandco)/admins can lock and unlock accounts,when required.

In terms of ban, yes: Perma ban, temp ban and nuke(only applies for newbies).

There were shadowbans for newbies,I don't think they still exist though.

All the 3 cases apply when the original user/ hacker tries to change the password and email, the time of when the last account was used is what makes the messages differ.