It seems like Facebook return this following error when you hitting that revoke error:

Error validating access token: The session has been invalidated because the user changed their password or Facebook has changed the session for security reasons.

What this error mean is some how that access token already different that time you authenticated with your facebook account, or recently changed the Facebook user password.

By the way, I still unable to replicate this after i manually delete that Facebook row data from this table -> #__discuss_oauth .

This is what i tested just now, after delete it, then i re-authenticate again and try revoke access, it seems work fine for me.

Perhaps you can try monitor and see whether you still remember what you did recently which related those Facebook login stuff, it might help us to identify this issue.

So it seems to only do it with EasyDicuss, i'm not sure what you may have coded different between easysocial, easyblog and easydicuss, but some thing is different, It posts fine when coming out of Easyblog but not Easydicuss the apps are the same, i'm using the same app for all of it, so i'm not sure what may be going, It was sorted in the latest version of Easysocial so may be its also related to the same issues the issues about the session

Yeah about the revoke, some times it works some times it doesn't could it be cache or Cookies causing an issue?

best

I would suggest that it would be better use different Facebook app for each of the component setup, if not it will get conflict by doing that.

For example :

Easyblog/Easydiscuss Facebook autopost authenticated with your Facebook app.
EasySocial Facebook login authenticated with your Facebook app.

How the revoke access work is, it will remove this authenticated Facebook app from your Facebook account (same concept like you can remove your app from your Facebook user setting here (http://take.ms/FhAjn ) so when you click sign in via Facebook button, it will show the pop up and ask for those permission.

And I just recall I got encounter one of the Facebook login issue in previously, for some reason Facebook unable to give us that access token when the system request Facebook for login, in order to make the system request to the Facebook, it needed to request Facebook to regenerate that current user access token for the login, I suspect this might be causing this issue so you unable to revoke access from your Easydiscuss, because your Facebook user access token already different, this is why Facebook return this following error when i troubleshoot into your site just now.

Error validating access token: The session has been invalidated because the user changed their password or Facebook has changed the session for security reasons.

Perhaps you can try setup another new Facebook app for Easydiscuss and see how it goes.