As of a few days ago I am no longer getting Contact Form 7 emails from people with a @yahoo.com email address. They are getting the mail2 message that is sent to them but I am not getting the original message. I've tested this on two websites using different contact forms on each and it is the same issue. The @yahoo.com senders have even replied to the mail2 message and I've gotten those without an issue. I do get orders successfully via WooCommerce from people with @yahoo.com addresses so I know it isn't a Gmail issue or a server issue. And I get emails from other domains without a problem.
I did set up Flamingo this morning and it is capturing submissions from @yahoo.com people that are certainly not going though. The sender gets the mail2 message but I still don't get the main submitted form via email.