What is wrong with this picture? (no replies)

Marlin ver bugfix 2.0.x.8cfcabe
Repetier v2.1.6

I home all with G28. Home is set to backoff 30mm
I then run this script

g0 x50 y50 ; place XY on bed
g28 z ; home Z and raise to 30mm (backoff)
g0 z0 ; Z=0 = measure offset

It goes to x50, y50
then homes Z which ends up at Z=30mm
then it move Z to 0 to test my offset which is set at 0.20mm

Repetier Log
20:23:54.770 : N79 G28*45
20:24:03.945 : X:0.00 Y:0.00 Z:30.00 E:0.00 Count A:0 B:0 Z:24000
20:24:11.405 : N80 G0 X50 Y50*16
20:24:11.405 : N81 G28 Z0*96
20:24:11.405 : N82 G0 Z0*89
20:24:21.634 : X:50.00 Y:50.00 Z:30.00 E:0.00 Count A:20000 B:0 Z:24000

So why is Marlin saying it is still at Z=30? The probe actual position is about 0.10mm from the bed. (paper thickness)
If I click Z 1 + step, Z rises to 31mm.

21:01:42.183 : N100 G1 Z31 F1000*54