While this is not an explicit bug, it might be misdiagnosed as one.
This has to do more with the nuances of the Taplytics product and properly using the "resetUser" method call.
Why you might see more devices than the number you currently have to test could be the case where you’re rebuilding new versions of your apps and app users are not getting registered and de-registered properly.
If you’re re-building your app with different versions and build numbers during QA and deleting/re-installing without logging in and logging out, each install will be most likely show up as an entirely different user.
To get around this, we have a resetUser call that can deactivate the old users when you logout. Please see our iOS SDK documentation https://github.com/taplytics/taplytics-ios-sdk/blob/master/START.md#resetting-users