[Observium] A graph that doesn't quite match the data

Hello,

Here's a screenshot of 2 Traffic graphs for a 10G port on a Cisco 6509. The second (week) graph seems accurate, with the spike indicating a little over 300M bits/s. The first (day) graph indicates that the same spike is only 200M bits/s. The actual numbers under the graphs agree that the max is 337.03M.

Traffic

Why doesn't the first graph show the actual value?

This is on v 18.3.9125.

Thanks,