[bug] false negative info out of roundcube

[Marco31Bike]

Email server - PERFECT
YF 6.5 - ALL PERFECT

sending email from account1@mydomain.com to account2@mydomain.com and roundcube ext. reporting:

Watch out for this message, the email address in the From field has been forged.
Do not click any links, download attachments, or provide personal information in response.
Sender: Incorrect

To make sure that everything is fine, I send the same email to mail-tester and score is 10/10

It may be deemed as insignificant issue, but it is at least important to know what pattern of detecting quality of incoming/outgoing email is measured in core.

I would threaten it as a bug... nothing biggy, but bug which undermining impression of quality programming.