[5.6.0-beta.1] Support Z-distance feedback: Support thickness of 0.01mm on layer 0

[printingotb]

Cura Version

5.6.0-beta.1

Operating System

win10

Printer

Custom fff

Reproduction steps

see project. The model is a 10x10x0.2mm square raised 1mm above the buildplate. It has 3 layers of support.
Layer height and initial layer height is 0.2mm. Support Z-distance is 0.39mm

Please also see my other reports submitted at the same time, some are related.

Actual results

The Z coordinate at layer 0 is 0.01. Wrong?
Also, the normal support lines on layer 0 gets reduced like I would expect the topmost support interface layer to be. I assume because it "believes" it's the last layer of support?
Note, I discovered that the extraneous normal support lines disappear when I reduce my support horizontal expansion. I had set it extra high to make testing easier.

Expected results

Z-coordinate on layer 0 should be same as initial layer height?
I believe printing a 0.01mm thick first layer risk damaging the buildplate, especially if the bed is leveled a bit too close to the nozzle. (This is why I moved the support structures upwards in my script-attempt instead of downwards #6105 (comment)).

Add your .zip and screenshots here ⬇️

Layer 0 Z.3mf.zip

[GregValiant]

BIG EDIT:
Thanks for the report.
When I slice you file I get this at Layer:0 IN CURA 5.5.0
;--------------------------------------
;
G92 E0
G92 E0
G1 F1500 E-0.8
;LAYER_COUNT:6
;LAYER:0
M107
M204 S1333
M205 X5 Y5
G1 F600 Z0.4 >>>>> This is Initial Layer Height of 9.2 + ZHop Height of 0.2
G0 F6000 X103.834 Y103.834 Z0.4
M204 S1000
;TYPE:SUPPORT
G1 F600 Z0.2 >>>>>This is "Hop down"
G1 F1500 E0
G1 F1373 X103.948 Y103.803 E0.00425
G1 F1488.8 X116 Y103.8 E0.40407
and at the beginning of the file is ;MINZ:0.2

In 5.6beta2 I can duplicate this behavior.
;--------------------------------------
;
G92 E0
G92 E0
G1 F1500 E-0.8
;LAYER_COUNT:6
;LAYER:0
M107
M204 S1333
M205 X5 Y5
G1 F600 Z0.21
G0 F6000 X104.2 Y104.2 Z0.21
M204 S1000
;TYPE:SUPPORT-INTERFACE
G1 F600 Z0.01
G1 F1500 E0
G1 X115.8 Y104.2 E0.38196
And the beginning of the file shows: ;MINZ:0.01
@MariMakes this one needs some attention. I am unable to duplicate the behavior with my printer active.