AP Calc BC subscore issue

I took the AP Calculus BC exam and saw that I got a 5 on the AB subscore and a 3 on the BC exam as a whole. I’m confused how this is possible. I saw on the college board website that AB material makes up approximately 60% of the exam, and I know you only need to get around 50-60% correct on the BC exam to get a 5. I feel like a 5 AB subscore should get me at least a 4. Especially considering I felt confident in the BC material as well.
I was wondering if anyone else has had this issue or if anyone has any advice on what I could do to make sure the 3 wasn’t a mistake.

It is not uncommon. Usually they are close, but I have seen 5/2 and once I even saw a 5/1. It is all mathematically possible.

The scores aren’t necessarily linear. Why does a 50-60% on BC resulting in a 5 mean that a 5 on AB should yield a 4 on BC.

I’ve seen 5AB/2BC and I’ve seen 4AB/5BC.

If you believe it’s a mistake, you could request a multiple choice rescore. But it’s almost certainly not going to change.

Only if you took a paper exam.