We've used WP Super Cache for years without a problem. During the last week we've experienced major issues with 6 different WordPress websites running on 5 different themes all on WP 3.71. At first, we thought it might just be the 3.7 upgrade as some post have stated. There still may be issues with that.
Last Tuesday, we moved all our websites from a legacy server environment at GoDaddy that used a single port running on Apache 2.2 to a load balanced grid server environment running Apache 2.4. Since then, every one of our websites started experiencing 500 internal server errors whenever we updated the MySQL datebase. Godaddy spent hours yesterday investigating everything possible on its servers and the error logs we've been running. It was exhaustive and they found nothing amiss.
Not only were we experiencing these server errors working in the backend of WP, when we would visit the sites, we would get a blank screen. Additionally, the WP Super Cache test started showing a time stamp difference on all six installations. When we deactivated WP Super Cache, it went to white screen again and required many refreshes even to accomplish that. Same when we deleted it. Now that we've deleted it on all our websites, they are functioning normally again.
Obviously, there are a lot of variables that could affect what is going on. Is it the new WordPress? Is it the load balancing server structure or Apache 2.4? Is it some combination of all of these? With the exhausting checking of our server environment and addressing all error log issues for a problem that was occurring on different WP installations with different themes, it appears that the culprit most likely is WP Super Cache.
We encourage the developer to investigate this and test out the plugin in the server environment we have described to see if there are, in fact, some coding issues that need to be addressed.