Data does not match Y axis values

I’m running grafana-5.3.4 on a Linux system, which is querying an InfluxDB database. One of the graphs that I’m using renders data from 2 different queries. One of the queries if fine (temperature). However, the other query (AQI) does not line up with the Y axis values correctly. This image illustrates the problem:

Is this a bug, or am I potentially doing something wrong?

thanks!