Thank you for your prompt reply. When I contacted Jetpack last (August 2018), I only mentioned the issue of regular commenters being sent to Spam or Moderation because that was the first commenting error that I was aware of. At that time, the Jetpack Happiness engineer advised me to clear my comment moderation list (which I have done completely). He then advised me to reach out to the WordPress Community if I had further difficulties (which I have since have).
I will email Jetpack now with these details and the previous discussion.
Hi, Steven – Thank you for your prompt reply. I will go back to Jetpack and see what they say. Thank you for the link.