CR-10 randomly pauses for a few seconds
Edit: The z-hop problem has been fixed in Cura 4.2.



This is a known issue with Cura 4.1 when z-hop is enabled.

If you touch the z-axis motor frame while it is apparently stationary, you may feel it is actually moving.

The solution is to set a value (I used something like 250 in conjunction with an Ender 3) for the "Maximum Z Speed".

First you need to get the setting to be visible, so go to the "Settings" menu and choose "Configure setting visibility...":



Then in the "Print settings" panel:



The full story is available on GitHub at [4.1 - current master branch] Z feed rates #5753.