Of course … yes. You’ve exceeded the limit. Gotcha. -- Don’t really think it’s an error. I think (with emphasis) that you lose activity feed visibility once you exceed that limit, so …
Here’s the thing with the tracking … it’s normal to receive multiple notifications when tracking is on. We’ve seen cases where email clients trigger ‘opens’ when recipients simply scroll through their emails. Actually tested this while on the phone with a client using Outlook over the 2017 x-mas holiday …
He was like, “Wait. What? You mean you can see me scroll through my email?” … and I’m like, “ok. No. That’s that what we mean when we say we can see WHEN you open your email.” haha Naturally, the conversation de-evolved into conspiracy theories and cookoo’s nest paranoia after that. I think his eggnog was spiked. 
Gotta get you on at least Sales Pro. haha
Good luck on your project.