To be clear, I don’t believe that this is necessarily a SpamSieve issue, but it is Mail related, and I’m pretty stuck.
My issue: Mail always shows “downloading messages” in its Activity Window. And it appears to consume memory faster than it used to (I need to restart Mail on my SpamSieve drone every 3-4 days now; used to be able to let it run for 2-3 weeks before memory use got excessive).
I’ve posted to Apple’s Communities here https://discussions.apple.com/thread/7938953. You can find the history of what I’ve seen and done there. No responses yet.
I have gone through and disabled all mail accounts and then enabled them one by one. Hasn’t helped to narrow things down.