Not Enabling Plugins correctly

I had several problems with the plugin. Sometimes I define a plugin to be active for a certain post type, and certain specific URL′s of this post type would not activate the plugin. I have some plugin filters that do work sometimes, but not always in activating the right plugins. And once I tried to even activate some plugins on a specific page and it did not work either. What could be the issue in causing me so many problems? The problem appears on a sub site of a multisite network and being hosted on Siteground.