Warning G92 emulation unable to determine all coordinates to set

[Joymaker]

I am using GPX for my flash forge Creator Pro. Invoking as follows:
gpx -m r1d "Tiny square 10mm.gcode”

I get the following message, twice:

(line 20) warning G92 emulation unable to determine all coordinates to set via x3g:140 set extended position
current position defined as X:0.00 Y:0.00 Z:-5.00 A:0.00 B:0.00

By counting actual lines of code and ignoring comment lines, I get that line 20 is probably:
G92 A0 B0 ; zero extruders

If I press on and print anyway, the printer goes through its normal preparation process beautifully, but then, when the head should move to center to begin printing the object, it moves to the origin corner instead, and then of course prints things where they ought not to print.

Is there a good fix for this?

The entire beginning G code is as follows:

; generated by PrusaSlicer 2.9.0 on 2025-04-01 at 13:17:56 UTC

; external perimeters extrusion width = 0.45mm
; perimeters extrusion width = 0.45mm
; infill extrusion width = 0.45mm
; solid infill extrusion width = 0.45mm
; top infill extrusion width = 0.40mm
; first layer extrusion width = 0.50mm

;TYPE:Custom
G90
M83
M127
; **** Replicator 1 dual start.gcode ****
M73 P0 ; enable build progress
G162 X Y F3000 ; home XY maximum
G161 Z F1200 ; home Z minimum
G92 Z-5 ; set Z to -5
G1 Z0 ; move Z to 0
G161 Z F100 ; home Z slowly
M132 X Y Z A B ; recall home offsets
M135 T0 ; load right extruder offsets
G1 X150 Y-70 Z30 F9000 ; move to wait position right hand side of the table
G130 X20 Y20 Z20 A20 B20 ; lower stepper Vrefs while heating
M127
M140 S60 T0
M134 T0 ; stabilize bed temperature !!!
M104 S210 T0
M133 T0 ; stabilize right extruder temperature !!!
G130 X127 Y127 Z40 A127 B127 ; default stepper Vrefs
G92 A0 B0 ; zero extruders
G1 Z0.4 ; position nozzle
G1 X110 Y-70 E25 F300 ; purge nozzle
G1 X120 Y-70 Z0.15 F1200 ; slow wipe
G1 X110 Y-70 Z0.5 F1200 ; lift
G92 A0 B0 ; zero extruders
M73 P1 ;@body (notify GPX body has started)
G21 ; set units to millimeters
G90 ; use absolute coordinates
M82 ; use absolute distances for extrusion
G92 E0