Marlin: Why is the extruder stepper jerking?
The setting that makes these small retractions is LIN_ADVANCE.
It is found in Configuration_adv.h and is disabled in the vanilla configuration.
I, on the other hand, is using one of the 46 example configurations that has this feature enabled. It shall be said that most of them them has the value 0 set to this, which means that it has no effect.
To disable the effect of this feature, send G-code M900 K0 to the printer.
More info at marlinfw.org
More info at 3dmakerengineering.com
M900 - If it works, the feature is enabled
Test pattern generator to tune LIN_ADVANCE