Hi Brian,
I just checked and found this is a new issue, I just raised it as DE33764.
It is still happening on 15.2 on Capacity vs Allocation by OBS. We will work on a fix and let you know once it's available.
If you need a very quick solution, and have the ability to work with SQL, then you could copy the report query and correct it to use round functions in a new 'custom' report. Alternatively you could suggest to users to uncheck Show Graphs if that's distracting to them.
Hope this helps -Nika