cnc router x axis starting before y axis finished when pocketing ?

[Robin Oakapple]

Details like cutting parameters...

Thanks for the extraordinarily detailed response Jazz, it's very helpful and has given me much to study and experiment with.

By the way, the pockets in the pictures are 150mm by 30mm, 3mm deep and cut with a 6mm compression bit from the Cutter Shop in Fareham. The Gcode was generated in Vectric Cut 2DPro and run by Mach3 to my 1220 x 850 (with 2.2Kw spindle) router which was made by RNR Designs in Stockport.