I have frequently and repeatedly had the problem that Todd describes, and it is not a new phenomenon.
Google Groups has many nice features, but it has a number of technical quirks that require me to use a variety of workarounds to accommodate the website. Google does not allow me to participate using the email address I registered at Wikitree, apparently many of my posts get held for moderation (I often am unsure whether other group members can see my posts), and I often get warnings from Google saying that my post to a Google Group looks like it might be spam. When someone sends a PM to a project account's Google Group, I usually cannot reply to the message; if I need to reply, I need to copy the address into a new message. And now this.
I know that the desire for a replacement has been on the Wikitree Tech to-do list for years, and I wish it had higher priority, because Google Groups exacts a high overhead cost on my participation.