Thanks for that plugin link, it will probably solve the problem.
Yes I know SP does not output og tags. But the description title and tags do not show up when yoast is active. Disabling it for the forum page will solve the problem, just like toggling aio seo off on the forum page.
All I know is, no matter how the setting are in sp seo component with yoast active they do not show in any forum page view page source. So it's blocking sp meta (title desc keywords and canocal) hats all I know.
but thats my point... those topics I linked to show you how to set a couple filters so that ours override wordpress seo so title, description, keywords and canonical url all come out...
but agree, the plugin will solve it all for you...
the page header tags are the most 'abused' thing by themes and plugins... its not that anyone blocks them, its that the last one to run, wins... it overwrites all the other guys... themes want to set the head tags, seo plugins do, other plugins do, then plugins like simple press have to try to override because the seo plugins just get it wrong for dynamic pages (hence why aioseo has an option to disable on page by page basis)... unfortunately, there is not any one set of filters and priorities that we can use that work across all themes and plugins... so for some, you just have to use a filter and change the priority (what those links do)...
That makes sense about what plugin runs 1st, appreciate that. Sometimes it don't sink in at first.
After searching the source on an sp post page i found the description and keywords meta tags further down in the source. But when putting the page %%xxx%% back in Yoast page template area it wiped that data out. Neither of your examples on the other post made any difference either way, that i believe dealt with the canonical url, which was correct before.
So from what I'm seeing, removing "%%title%% %%page%% %%sep%% %%sitename%%" from Yoast setup > Titles and Metas > Post Types > Pages did the trick. However if you have a lot of pages that need seo on them other than the sp forum page it might not be a good option.
One good thing is, i had installed a page featured post, a forum button, which is now included in the pages og-tags as default image. It will make sharing forum posts with FB show an image now.
Once again, thanks for all your help. 
did you ever try the plugin organizer?
