RX battery

I bought a 73RX from Best Buy about 6 month ago. I’ve got 274 miles on it. I haven’t had any issues with the bike other then when I hit 24% battery life it immediately drops to 10% and I lose 99% power. A few times it’s gotten as low as 18% then dropped to 10%. I use my iPhone so I’m running the super73 app and that’s where I’m getting my %’s from. I never think to check the controller and compare it with what the app says. Any help would be greatly appreciated it!

Edit: a couple friends of mine have Brooklyn’s and theirs doesn’t jump like mine from 24% to 10% but my % doesn’t seem to drop much faster when we are all pretty much charged up.