Last Values = 0 on Report Charts

I've noticed on a lot of charts for reports we get this weird line shooting downwards a the end of the report. Looking at the XML data for the report, it does in fact show the last value for many of the fields to be 0. Any ideas for a work around or what I have done wrong?

I've played around with chart settings and have never gotten a setting combo that works to fix it. Current settings below.