I used to prefer it for it's simplicity, but there are (or were) things that you can do on the webpage that are difficult in Tapatalk, so I occasionally had to use the website anyway. But mostly I used Tapatalk because I followed multiple forums. Having one place to go was convenient. Now that I only follow this forum, and I am used to the website version, I have little reason to use Tapatalk.
If I ever go back to following multiple forums, I'll probably revisit it. That's the app's biggest advantage in my experience; one consistent tool to follow multiple forums.
As for your issue/question I can only postulate.
Most forums are under constant attack by spammers and phishes who use bots to create new users and posts. These bots often attack with multiple fake users and on multiple forums at the same time. Mostly they get cleaned up by admins within an hour or two of posting. Maybe your timing was bad and you got a ton of these from multiple forums before they got cleaned up. Or maybe they trickled in, but Tapatalk did not update the posts when they were cleared by the admins.
The other possibility is that Tapatalk was attacked with malicious ads. I don't know if the app still allows ads, but I'm pretty sure the free version did at one time.
To the best of my knowledge this forum does not support the kind of notification you saw. Maybe others you follow do.
Anyway, those are my best guesses based on what I can see. If you can trace the origina back to a specific forum or Tapatalk itself, it probably won't hurt to report it to their support. Especially if it bypassed the normal forum posts and hit your direct message inbox. Otherwise, there isn't much you can do about it except let the forum clean it up.
Personally I've learned to recognize this kind of post here, and just ignore it. I'd rather not give the people involved any kind of feedback, positive or negative. I know it won't happen, but it would be great if their time and money was all fed into vacuum, with no result to show.