Mac Mail size column does not include attachment size

Well - I confess this problem has just disappeared ! After a few days connected, all the mails show the correct size now - must have been the mail catching up with the mail server on the new machine. Thanks for all the replies, it seems to have been simply a matter of being connected long enough for the full information to come through.

Thanks, but this is not so in the mailboxes that I see. I have checked some of the old messages saved save under On My Mac, and the message size shown for them does indeed include the attachment size - (those messages were downloaded and saved under Catalina). But the mailboxes message size does not include the attachment sizes under Monterey, which it does under Catalina. I have IMAP mailboxes from two providers and the mail behaviour is the same with accounts from both providers. The Mail accounts settings are IMAP, and all settings are identical on the two machines.

I attach two pics - the size of same email in the same IMAP mailbox viewed from Mac mail on the two Macs. 

Catalina -

Monterey -

Thank you - yes that is the view I am using, but the size only shows the email message size not including attachments.

Size in the submenu is of course enabled - wouldn't be able to see it otherwise ! I've just responded to Luis.

Glad it's OK for yourself and others, but I am also on Monterey 12.5, and sadly the message size shown does not not include the attachment for me.

Thanks. As no easy answer has appeared yet, I've also been thinking the same way - the mail providers should be the next port of call. FYI - I don't use Gmail