I am also facing similar issue when scheduling meeting via Teams Channel.
From a newly created teams channel, whenever the invite is sent to selected participants, the invite is eventually going to all members.
While scheduling the meeting, I see the option to send the personal invite is disabled already. But seems no effect of this option.
Another strange issue is, inclusion of extra participants under optional which is visible only after sending the invite.
Both issues are annoying the users who are not the intended participants and getting unwanted invites in their mailbox.
Microsoft Teams version is - 24295.605.3225.8804.