It’s not only title tags, you will also get duplicate Meta descriptions when you paginate. It’s such a shame that Yoast is considered an authority on SEO and yet this plugin can get you penalized by Google.
I had to stop using the plugin 3 days ago. If you don’t find a solution, you can use Ultimate SEO plugin, it will append the page number on your titles and Meta description when you paginate.
Have you looked at the template settings in the WordPress SEO -> Titles page?
There are a couple of options of pagination in the title and meta description fields.
Look towards the bottom of the page.
I tried saving %%title%% | %%pagenumber%% and it doesn’t work
Just %%pagenumber%% doesn’t work or nothing works? Have you tried %%title%% | %%sitename%% to see if that works?
%%title%% | %%sitename%% works fine although I have noticed that it will be overridden if you enter SEO title when posting.
%%pagenumber%% and %%page%% do not work
If you set a title on a page or post then that will take precedence over the title template. I believe that is the intended behavior.
Do you have a test site or can you disable other plugins? Maybe something is conflicting with the pagination values?
From the sound of things, SEO titles is working but the %%page%% and %pagenumber%% tags are not.
