I'm not sure if that's layer-thickness problem, but i suppose yes,
defects inside and outside the gearwheel (especially inside one is problematic..):
auto-calibrating (before and after): all 0.0
(ps. black arrow shows where front of the printer was if that has meaning...)
I don't think .39 is really usable right now. There is quite a bit of delamination. Try .29 for better results.
We'll fix it in next update.
For that resolution you need to use 100% fan, the amount of deposited material is to much. We have tried that resolution also and fan isn't capable to cool that much material so it starts to hang even with smal angles. Try that and see if it improves.