I seem to have fixed the problem for myself by clearing the cache, deleting the SA cookies, and reloading.
I can't see comments either for any article except ones from SA Editors. Example of no comments available: https://seekingalpha.com/article/4129224-6-s-and-p-500-stocks-tagged-20-percent-49-percent-november-net-gains-per-broker-targets
Example of comments available:https://seekingalpha.com/news/3315859-stocks-watch-next-week
The feed still shows the comment count, and the alert system still tracks new comments, but when I click on the article, I cannot see any comments.
The change for me started several days ago.
Customer support service by UserEcho