After a lot of scouring, it looks like if we disable the System - wbAMP plugin, our JFBCContent plugin properly works. I haven't done any further testing to understand what the wbAMP plugin is doing, but that's the culprit.
Is that something you're using? What is it's purpose? In the configuration of it, I see on the "Plugins to disable" list that the JFBConnect plugins are listed. So, whyever you disabled those is what's causing our plugins to be... disabled. If it should only be disabling those on AMP pages, which I'm assuming is correct, then it seems like there's a bug in the wbAMP plugin that you may need to contact them about.... or remove our plugins from being disabled.
I hope that helps.
Alex