Dramatically slow build time when used together with webpack's IgnorePlugin

[jordan-meraki]

I am using a private corporate repo that uses webpack. This plugin reports that the IgnorePlugin step alone takes 21 minutes (the whole build takes 45 minutes); however, when I remove speed-measure-webpack-plugin the build takes 5 minutes total.
Also if I remove IgnorePlugin it is much faster also.

So any combination of the two causes a dramatic slowdown.