Delta calibration Issue Marlin 2.0 / Geeetech G2S (no replies)

I am trying to configure Marlin 2.0.5.3 (sunday's bugfix build) for my Geeetech G2S. I used the default configuration from the Marlin configs folder [github.com] and added #define DEBUG_LEVELING_FEATURE.

Now after booting up I run M501 to check EEPROM consistency with the defaults. This confirms

echo:; Delta settings: L R H S XYZ
echo: M665 L196.00 R90.00 H200.00 S160.00 X0.70 Y0.05 Z-0.74
[...]
echo:; Z-Probe Offset (mm):
echo: M851 X19.00 Y-11.00 Z-2.00

Next step enabling debugging: M111 S247 and then running G28 correctly tests all three towers then moves down to Z 146mm:

[...]
<<< do_homing_move(Z)
<<< homeaxis(Z)
>>> set_axis_is_at_home(X)
current_position= X0.00 Y0.00 Z212.00 :
<<< set_axis_is_at_home(X)
>>> set_axis_is_at_home(Y)
current_position= X0.00 Y0.00 Z212.00 :
<<< set_axis_is_at_home(Y)
>>> set_axis_is_at_home(Z)
current_position= X0.00 Y0.00 Z202.00 :
<<< set_axis_is_at_home(Z)
current_position= X0.00 Y0.00 Z202.00 : sync_plan_position
current_position= X0.00 Y0.00 Z202.00 : <<< home_delta
>>> do_blocking_move_to X0.00 Y0.00 Z145.97
destination= X0.00 Y0.00 Z202.00 : destination = current_position
destination= X0.00 Y0.00 Z145.97 : prepare_fast_move_to_destination
current_position= X0.00 Y0.00 Z145.97 : zone border move
current_position= X0.00 Y0.00 Z145.97 : xy move
<<< do_blocking_move_to
echo:Active Extruder: 0
X:0.00 Y:0.00 Z:145.97 E:0.00 Count A:25607 B:25607 C:25607
<<< G28
ok P15 B3

Then I turn UBL on: M420 S1 and G29 AON (guess this is redundant) and run G29 P1. Why does this operate on Z100? Shouldn't it move down to the bed to invoke the probe? The exact output:


Probing mesh point 25/25.

>>> Probe::probe_at_point(44.50, 0.00, raise, 0, probe_relative)
current_position= X0.00 Y67.50 Z100.00 :
>>> do_blocking_move_to X25.50 Y11.00 Z100.00
destination= X0.00 Y67.50 Z100.00 : destination = current_position
current_position= X25.50 Y11.00 Z100.00 : xy move
<<< do_blocking_move_to
echo:busy: processing
current_position= X25.50 Y11.00 Z100.00 : Probe::set_deployed
deploy: 1
Probe::move_z(10.00)
>>> do_blocking_move_to X30.00 Y90.00 Z100.00
>>> do_blocking_move_to X0.00 Y90.00 Z100.00
destination= X25.50 Y11.00 Z100.00 : destination = current_position
current_position= X0.00 Y90.00 Z100.00 : xy move
<<< do_blocking_move_to
>>> do_blocking_move_to X0.00 Y67.50 Z100.00
destination= X0.00 Y90.00 Z100.00 : destination = current_position
current_position= X0.00 Y67.50 Z100.00 : xy move
<<< do_blocking_move_to
echo:busy: processing
current_position= X0.00 Y67.50 Z100.00 : Probe::set_deployed
deploy: 0
//action:notification Probing Failed
Error:Probing Failed
<<< Probe::probe_at_point
current_position= X0.00 Y67.50 Z100.00 : Probe::set_deployed
deploy: 0
>>> do_blocking_move_to X0.00 Y0.00 Z100.00
destination= X0.00 Y67.50 Z100.00 : destination = current_position
current_position= X0.00 Y0.00 Z100.00 : xy move
<<< do_blocking_move_to
X:0.00 Y:0.00 Z:100.00 E:0.00 Count A:21929 B:21929 C:21929
//action:notification 3D Printer Ready.
echo:Active Extruder: 0
ok P15 B3

What am I missing here? Did I omit a step? How can I test probe activation/recognition? The microswitch and the cable are OK, I tested those.

In case you want to the my priter levelling 100mm above the bed:

[youtu.be]

Thank you four your help!