Mail suddenly is not showing the proper return address for my emails

I have multiple email addresses. In the past day or so when I have gone to reply an icloud (@.me) email, it wants to send from my old grad school account and does not give me the option to use the preferred account although it does allow me the option of hiding my email.

When I go into preferences and check the accounts tab, the icloud/me account is properly in its place. When I go to the composing tab and check the Send New Messages from drop down, my icloud/me is NOT an option. This will resolve itself after awhile and then happen again. I cannot correlate any action to something starting or stopping this bug. Anyone out there have any thoughts?

Also the automatic OS descriptor in this post says 10.13. I am on is Sonoma 14.14.1