Stabilize mode does not affect elevator on a bench-test?

ScoutE.param (20.0 KB)
I find this strange: upgrading an old plane from AP3.8.3 to AP4.1.7 and bench-testing I see that stabilize mode does not move the elevator 30° pitch down produces 2us change on the elevator servo. (ailerons work fine)
However: Cruise mode controls the elevator too, just as expected.

What am I missing? - I know that I have seen decent output on both aileron and elevator as a part of preflight-checklists before.
Params attached.