This came from [a comment in this PR](https://github.com/elastic/kibana/pull/23013#issuecomment-426897839) where we shouldn't show negative values on the y-axis for graphs showing percentages. I'll go back and add the list of known affected graphs later. It might be as easy as [applying this logic](https://github.com/elastic/kibana/blob/master/x-pack/plugins/monitoring/public/components/chart/chart_target.js#L53-L55) for the y-axis too
This came from a comment in this PR where we shouldn't show negative values on the y-axis for graphs showing percentages.
I'll go back and add the list of known affected graphs later.
It might be as easy as applying this logic for the y-axis too