Hello! Little delay on answer in these days (until 1st October)
I noticed that all the Forum pages have the same title. It’s no good for SEO
But this is, as explained elsewhere, a resolved problem. I will try to implement in my bad Eng and try to explain in other words.
Bots only see real phpBB urls.
Are you using the v3 iframe code?
If you applied the javascript code into phpBB overall_header.html, you see that this code, execute only if the request isn’t from a bot.
So in this case, if the user have javascript enabled on browser, that is on 99% of cases, you’re redirected to the wp iframed page. Try this yourself, disable javascript on your browser, and point to real phpBB url. Of course, you’ll see that you’re not redirected to the wp iframed page, and full phpBB will open instead. This what a bot see and follow: full phpBB urls.
There are many aspects that we could speak on this argument, for example how bots threats javascript. We can suppose bots follow and analyze the js code, but may they follow links on page, and not what an instruction of javascript do and using this to index pages. This is not.
Other aspect are widgets that display last topics, posts in wordpress:
again, javascript do the job, an user with javascript enabled
will be redirected to the wp iframed page, but what a spider/bot see, are real phpBB urls.
To see that this is it, again, with javascript disabled on your browser, reload a wp page where a last post widget display, and click into a link: the full phpBB will open for you in this case. Re-enable javascript and reload page, then re-click: you’ll see that you’re now redirected to the wp iframed forum page.
On v3 js code (v4 is coming and all the iframe aspect rebuilt even for widgets, with easier, shorter and all fixed code), substantially, all the trick is done via javascript, and let bots index all phpBB pages, at their real url.
In other words, the fact you see forum’s pages with same name on top of the iframed WP page, isn’t an aspect that matter for spiders/bots. But only for browsers with javascript enabled.
Yes is possible to push whatever you like for forum’s page, making user’s experience even better, i will try to cover also this aspect with all others on v4 code. But this is just a cosmetic addition, that do not have nothing to do with spider’s indexing job.
Are you using the v3 iframe code?
https://www.axew3.com/w3/2018/12/phpbb-wordpress-template-integration-iframe-v3/