Toolsetter always works before running spindle, error sometimes after running it

o<toolchange> sub
;(debug, in change tool_in_spindle=#<tool_in_spindle> current_pocket=#<current_pocket>)
;(debug, selected_tool=#<selected_tool> selected_pocket=#<selected_pocket>)

;otherwise after the M6 this information is gone!
#<tool> = #<selected_tool>
#<pocket> = #<selected_pocket>
#<CurrX>=#5420
#<CurrY>=#5421
#<CurrZ>=#5422

; we must execute this only in the milltask interpreter
; or preview will break, so test for '#<_task>' which is 1 for
; the milltask interpreter and 0 in the UI's
o<chktask> if [#<_task> EQ 0]
o<chktask>     return [999]
o<chktask> endif

; Check if the requested tool number is 5000 or above. If it is, do not execute the measurement moves
o<chktoolnum> if [[#<tool> GE 4999.9] OR [#<tool> LT 0.5]]
        M6
        G43 H[ROUND[#<tool>]]
        G0 X[#<CurrX>] Y[#<CurrY>]
        o<change> return [1]
o<chktoolnum> endif
; Save state
M70
G90
;first go up
G53 G0 Z[#<_ini[AXIS_2]MAX_LIMIT>-0.1]

; then move to change position
; BvH: disabled on Sven request
;G53 G0 X[#<_ini[CHANGE_POSITION]X>-0.1] Y[#<_ini[CHANGE_POSITION]Y>-0.1]
;G53 G0 Z[#<_ini[CHANGE_POSITION]Z>-0.1]

; cancel tool offset
G49

; using the code being remapped here means 'use builtin behaviour'.
; In the manual change case, this displays the 'insert 6mm 2-flute endmill' dialog box.
M6

; run a few checks
o<svchk> if [#<_ini[TOOLSENSOR]SEARCHVEL> LE 0]
      M72
      o<change> return [-1] ; indicate searchvel <= 0
o<svchk> endif
o<pvchk> if [#<_ini[TOOLSENSOR]PROBEVEL> LE 0]
      M72
      o<change> return [-2] ; indicate probevel <= 0
o<pvchk> endif

G53 G0 X[#<_ini[TOOLSENSOR]X>] Y[#<_ini[TOOLSENSOR]Y>]
; load compensation parameters
G43 H[ROUND[#<tool>]]
#<toollen> = #5403
;(DEBUG, length from tooltable: #<toollen>)
G49

; Tool length shorter than 10mm is probably an error in the tooltable; the collet nut is already higher
; Adjust working set of variables to accomodate this situation
#<maxprobe> = #<_ini[TOOLSENSOR]MAXPROBE>
o<toollenchk> if [#<toollen> LT 10]
          #<Zstart> = #<_ini[AXIS_2]MAX_LIMIT>
        #<maxprobe> = [[#<_ini[AXIS_2]MAX_LIMIT> - #<_ini[TOOLSENSOR]ZABS_DNMOVE>]*-1.0]
o<toollenchk> else
         #<Zstart> = [#<toollen> + #<_ini[TOOLSENSOR]ZABS_DNMOVE> - #<maxprobe>]
        #<maxprobe> = [#<maxprobe>-[#<toollen>*0.7]]
o<toollenchk> endif
; Adjust extra probe safety distance if we run out of Z travel, then move Z down
o<lenadjust> if [#<Zstart> GT #<_ini[AXIS_2]MAX_LIMIT>]
  #<Zstart> = [#<_ini[AXIS_2]MAX_LIMIT>-0.2]
o<lenadjust> endif
;(DEBUG, Zstart after adjustment: #<Zstart>)
G53 G0 Z[#<Zstart>]

; Probe the toolsensor
F[#<_ini[TOOLSENSOR]SEARCHVEL>]
G91
;M62 P1 (toolsetter on)
G1 Z-1
G38.2 Z[#<maxprobe>] (probe in Z- direction until switch is activated)
o<probefail1> if [#5070 EQ 0]
          (DEBUG, Probing in Z- failed)
          ;M63 P1 (toolsetter off)
          M72
          o<change> return [-3] ; indicate probe contact failure to epilog
o<probefail1> endif
F[#<_ini[TOOLSENSOR]PROBEVEL>]
G38.4 Z2 (probe in Z+ direction for loss of contact)
o<probefail2> if [#5070 EQ 0]
          (DEBUG, Probing in Z+ failed)
          ;M63 P1 (toolsetter off)
          M72
          o<change> return [-3] ; indicate probe contact failure to epilog
o<probefail2> endif
;M63 P1 (toolsetter off)

G90
G53 G0 Z[#<_ini[AXIS_2]MAX_LIMIT>-0.2]

; Calculate toollen
#<toollen> = [#5063 + #[5203+20*#5220] - #<_ini[TOOLSENSOR]ZABS_UPMOVE>]
;(DEBUG, #<toollen>)

; Store new length in tooltable and activate length compensation
M72
G10 L1 P#<tool> Z[#<toollen>]
G43 H[ROUND[#<tool>]]
; move back to XY location before tool change
;(DEBUG, #<CurrX> #<CurrY> #<CurrZ>)
G0 X[#<CurrX>] Y[#<CurrY>]

o<toolchange> endsub [1]
M2