macOS Mail app is changing the outgoing server based on who I’m sending the email to

Just acquired a Mac Studio yesterday, getting it arrange as we speak.

macOS Mail app is changing the outgoing server based on who I’m sending the email to, as an alternative of utilizing the outgoing server & tackle of the account I’m sending from.

To describe the subject, I open a brand new email from account A and sort in just a few letters of the email tackle I need to ship an email to. It auto-fills and I press enter or tab to settle for it. Immediately the outgoing email server & tackle are modified to account B.

I’ve about 8 addresses for various companies and private use, and the privateness and separation from them will be essential in some situations.

Has anybody seen this conduct and have any clue how to cease it?

I simply switched again from Thunderbird and it took without end to arrange all the accounts on my desktop and laptop computer and telephone (there is not any simple approach to export and import, it is insane). Having to swap once more is going to make me bounce out my window.