Invalid SMTP ban when transfering mail via Thunderbird

[MelissaAutumn]

We have a case where someone recieved a invalid smtp command ban (as part of the stalwart's scan-ban policy) for apparently transferring their mail via Thunderbird's "Move to..." feature between inboxes.

2026-03-24T16:43:05Z INFO Banned due to scan (security.scan-ban) listenerId = "submission", localPort = 587, remoteIp = <snip>, remotePort = 59725, remoteIp = <snip>, reason = 
"Invalid SMTP command"

The bulk of the transfer was performed on mailstrom-prod-stalwart-1, eventually the user had to switch to a vpn to finish the rest and did so without issue.

I suggest we start logging smtp.invalid-command for a while to see what Thunderbird's doing.

[MelissaAutumn]

I've bumped smtp.invalid-command to log from debug. They should start logging.

[MelissaAutumn]

Hmm despite saving and reloading it doesn't seem to be logging. Looking into it.