Bumps at 90 degree corners, not every layer, looking for opinions

[TTVert]

I went ahead and printed a 20mm calibration cube using my maker select. I noticed that on the corners there are very tiny bulges in certain layers but not all. it also seems the imperfections are not throughout that entire layer just the corners. This is zoomed way in and is barely perceptible by my blind human eye but I could see it since the filament is so shiny. Tried a white PLA and the result was exactly the same but more difficult to see due to the color and lack of sheen.

Make select
1.75 PLA @ 190C/60C
60mm/s
.200 layer height

Thanks guys!

Dave