Machine stall after tool length probing

Yes, because you generally want to prevent moves if the spindle has been stopped but is still spinning.
I don't think that spindle-at-speed blocks G38.x moves (though I think it probably should). So I would guess that your code is stopping at the first G1.

You do have the option of setting at-speed permanently true if you don't actually have any spindle speed feedback.

But, otherwise, if you are using a timer, then it should be true 5s after spindle on and 5s (or maybe more) after off.

I tested following file:  
I wanted to test a G1 after a M3 command to force a wait for spindle-at-speed.
LinuxCNC stuck in Line 16.

Very strange.

Hm ok.
I need the feature that LCNC waits 5s until spindle relay switched on because the spindle has a external lock to prevent my fingers...
So how I have to configure it?
actual config:
relay-rrk-feedback => ladder timer TON 5s => spindle-at-speed

is this a solution:
on rising edge spindle.0.forward then reset ladder timer and spindle-at-speed then wait 5s and set spindle-at-speed
in hope that ther is no race condition.

But general I don't understand: If a M5 command was fired, why lcnc want to wait everywhere?

test_tasten.ngc works with G0 instead of G1.

G0 moves do not pause for spindle-at-speed.