Welcome! This forum has a treasure trove of great info – Scouters helping Scouters! Just a heads up, though - all content, information, and opinions shared on this forum are those of the author, not the BSA.
I just sent a normal BCC message to my unit parents. I received a copy of the email for every single recipient. The Reply-to field has been fixed, which is nice, except I received an individual copy for every single recipient as well. Each one was:
Yup. As @jacobfetzernoted above, the developers are now aware of the issue. It clearly worked before, so hopefully it’s a reasonably straightforward fix. Of course, I have no idea what else they changed that might have “broken” something in the background that would make reverting the code to the previous form impractical. Armchair coding is always in danger of finding things “Dilbert easy” (i.e. easy when done by someone other than the poster.)