Apple mail "organize by conversation" not working/works in Yahoo
My group emails used to be organized by conversation. About a month ago, it starting splitting conversations into separate threads. Most of the group replies come in one thread; replies from one or two other people come in another thread (it's always the same people that are "split" from the rest). The replies have the exact same subject heading and were "reply all". If I check my email via Yahoo Mail, the threads are intact, but I'd rather use Apple Mail if at all possible. I have a 2017 MacBook Pro and was using High Sierra (10.13.6?). I've toggled "Organize by Conversation" off/on without success. I just upgraded to Mojave (10.14.4) in the hope that might fix the problem, but it's still there. I've filed a bug report with Apple. Thoughts??
MacBook Pro 13", macOS 10.14