This is underextrusion.
If you did not already, calibrate your E-Steps/Extruder. See here: Extruder Calibration a must
If you did, my second guess would be that you have some oozing from the nozzle while it travels, losing pressure. Thats rather normal. To compensate, use extra prime amount after retraction/travel. That should help. See e.g. here: What Is Retraction Extra Prime Amount in Cura? (Detailed) - 3D Print Beast