Maryefern, have you had any luck with this issue? I have the same sort of problem on two sites I manage:
1. On site A, a long-time reader and commenter suddenly has all his posts held for moderation. He isn’t flagged by Akismet, and he hasn’t changed his user name, email, or IP address.
2. On both site A and site B, a long-time reader and commenter was made an “author” (different person for each site). In both cases, their comments are suddenly being held for moderation. I’ve checked the author settings, and nothing there indicates their comments should be held.
We have Akismet but not Jetpack. Both sites use the Going Green Pro WordPress template and are hosted by HostGator.
