u/Bartekoooooo

I have a BMW Z3 1.8 (M43, 118hp, cable throttle) and today I cleaned the throttle body because the car had slightly rough throttle response at low RPM.
After cleaning, I started getting a weird issue:
the throttle pedal physically sticks right at initial input
especially in 2nd and 3rd gear at low RPM
if I press a bit harder, it suddenly “pops” free and then becomes smooth again
in neutral and with engine off, it feels mostly normal/smoother
I removed the intake and inspected the throttle body more closely and I noticed what looks like a crack inside the bore near the butterfly flap.
The butterfly flap also seems to slightly rub/contact the bore at the fully closed position, which is why I’m wondering if the housing might actually be damaged or warped.
I attached a video of the inside of the throttle body.
My question is:
is this actually cracked/damaged?
or is it maybe just a casting mark or normal wear?
could this realistically cause the sticking throttle symptom?
The throttle body is mechanical/cable operated, not drive-by-wire.
Thanks for any help — I don’t want to replace the throttle body if this is actually normal.