After attempting to ugprade to the newest version of WordPress (and the newest version of Yoast), this following issue started:
Any time I added or edited a blog post, and/or edited a posts SEO settings in the Yoast settings, my .htaccess file was edited to include a line at the end that was some broken portion of the line (no quotes): "#END WordPress"
The line could have been any number of these combinations:
In other words, it was that "#END WordPress" but not complete. This incomplete line of code would cause the site to get a 500 Server Error whenever attempting to go to my url.
I've contacted my hosting, my theme developer, and wordpress, and they all say its a plugin causing this but they don't know which. The most likely culprit would be Yoast SEO because of the requirements for making this happen.
In the meantime I've restored a backup from right before I updated to 3.5.1 and the new version of Yoast (I'm using a version from January) and I'll stick with it for now, but has anyone ever seen this behavior or have any ideas about why it's happening? Or any suggestions as to what other plugin it could be that is causing it?
Obviously when the time comes that I NEED to upgrade, I'm just gonna have to upgrade each plugin one by one to see if/when the problem re-arises, but like I said, the most likely would be this one, so I figured I'd ask on here.
Thanks so much for your feedback/input.