Yeah, like Chris said this is likely because you don't have many add-ons that extend any classes installed. We had gotten probably 20 or so tickets from the issue, as well as several other replies to threads here. I put more details on this issue here, just to add more detail on the main issue (at least from what I had looked at -- literally opened a couple of PHP files and that's it)
I've rarely had an issue with TT and XF1 except that most addons don't get processed correctly by it, but then again the only thing I literally ever use it for on XF sites is to get push notifications on my phone, I see those then go to the site on browser lol
But it sounds like for the XF2 addon, they're really screwing the pooch from the get go
I highly doubt that will be true, or if it is, it won't be for long.
Honestly, we really don't pass comment very often on third party code, but this code must be avoided at all costs until they're able to release a version that extends XenForo code in the correct way. In its current state it is a compatibility nightmare, and if we did do any sort of code review, this wouldn't even be close to being approved.
Not related to code quality, and it's too complicated to generalize, but:
To all EU citizens here (and other companies doing business there too), are you aware that using Tapatalk can very well be illegal?
For some reasons now already, and with the new DSGVO in May 2018 there are plenty more reasons that may apply to you (and mostly will, for the average forum owner)
Not just for non-EU-companies - the DSGVO (which gets into force in May, and is one of the cases that is valid directly without a need for each member country to implement it in their own local laws) is about privacy, data protection and some related areas, and concerns for every company (inside too) and person alike.
... independent of legality, imo how the company Tapatalk acts towards admins/forumusers is more than horrible. How anyone can like that is beyond my understanding. Examples include anything from stealing your DB, to having paid trolls battling each critic and denying that they belong to Tapatalk even when there's evidence, hiding that they're hacked, introducing controversial "features" for their profit and conveniently forgetting to add them to the release notes, not honoring opt-outs they offered, trying to get your users to leave to other forums that are paying Tapatalk (better), not acting on a simple support request without threatening them with legal action, etc.etc.
(as I'm not using anything from them anymore, not all listed problems were witnessed by me personally. Parts of my list are from other internet sources that I deem reliable enough.)
Without spending too much time interrogating the quality and functionality of the code in general, I can at least confirm that the XF class proxy system is used appropriately and should resolve most previous concerns with interaction with other add-ons.