EMC Pluto-Step Z / Y axis interference (bug)??

[Paragon36]

I have just posted the below to IRC #EMC and thought I would seek advice here.

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I have a strange situation occuring :-
I have set max feed rate velocity at 900mm/min
When I execute G0 X100 Y100 it moves without error but when I try to return to Y0 I keep getting a joint following error?
If I hit F2 then enter G0 Y0 I get the error again.
Additionaly I get Z: 0.049 from 0.000 and the velocity shows as 7.500 ??
If I then hit F2 then G0 X0 it moves OK
I am using pluto-step with the following setup in the ini file...

Motion Control setup
BASE_PERIOD = 100000
SERVO_PERIOD = 1000000
TRAJ_PERIOD = 10000000
Traj setup
DEFAULT_VELOCITY = 4
MAX_VELOCITY = 15
DEFAULT_ACCELERATION = 5.0
MAX_ACCELERATION = 20.0

Axis Setup for all
MAX_VELOCITY = 15
MAX_ACCELERATION = 5.0
INPUT_SCALE = 1600
FERROR = 0.150
MIN_FERROR = 0.01

Additionaly if I just move with G0 Y100 it gets there but issuing G0 Y0 gives me the same error 'joint 2 following error'
Strange that it shows an error for joint 2 as this would pertain to Axis 2 (Z) right?
I think there is a bug within emc where the Y axis negative move shows as a Z axis positve move...
Just ran HAL scope and monitored Zpos-cmd, Ypos-cmd, Xpos-cmd triggering on 'pluto-step.stepgen.0.counts'
I can see Zpos-cmd and Xpos-cmd at the scope move as commanded but Ypos-cmd is not even displayed!!
Also when commanding Y in the negative plane I see Zpos-cmd changing with a raised step from HAL Scope!!

TIA
SRG