Inconsistent extrusion CR-10s

[DGFPlastic]

I am having some issue with gaps in my prints, they do not occur on every print and generally do not occur until above 50% in the Z direction.

Printer: CR-10s
Slicer: Simplify3D
Temp: 200C
Bed: 50C
.2mm layer height mainly
.95 extrusion multiplier
I've mainly been using Hatchbox PLA

It does not seem to occur at specific places in the roll so I don't think snagging filament is the issue, I've had it happen less than 50 grams into a new roll, 500 grams into a roll and near the end of a roll. I have 3 cr-10 printers, this issue does not occur on every print, my oldest printer(1000+hrs) has had this happen 1-2 times, my mid aged printer (400+ hrs) has it happen way way too often, and my newest printer (300+ hrs) never does this.

I have photos but it won't let me submit any links because I am new.

Thanks!