You answered your own question; it's not a genuine Apple battery.
Try this alternative which has an iOS or Mac version.
Then you are under warranty, make a Genius Bar appointment at an Apple Store.
No guarantees once you’ve installed an aftermarket battery. I’m not surprised.
If it is not an Apple battery then I cannot see how Apple come into it. I suspect you may be thinking about the current low cost offer and the reasons. I'm not sure but I have read that the adjustments Apple made to bring the problem about have now been removed or will be with the next update.
In any event it is now water under the bridge as far as you are concerned. You chose to do it yourself.
Thanks. I actually have used that. It shows i have 86% life left. I want to maje sure apple is not throttling me, though.
Thanks for taking the time to leave that extremely helpful reply.
I have this same exact issue, except my battery was installed by Apple in February.
Battery health won’t load
