Are continuously increasing antibodies from a covid infection from 14 months ago a sign of viral persistence?

I sent some blood to the labs and both nucleocapsid and spike antibodies were positive. My last infection was April 2023.

I previously tested spike antibodies 5 weeks ago and they were high at 19994.9 (whatver units) where range was < 50 and today it was 20424.1, so they've only increased.

Surely this is not normal. How can your antibodies keep increasing nearly 14 months since your last exposure unless there's viral persistence of some kind? Surely this is evidence that there's spike circulating in my system.