Peak times of FlashCam reconstructor seem off

[maxnoe]

Describe the bug

The peak times produced by the FlashCam extractor seem flat and don't show any structure in the shower at all, especially compared to the same event in NectarCam:

To Reproduce

Look at dl1 image / peak time of a nice FlashCam shower

Expected behavior

See a clear time gradient in the peak times.

Supporting information

The plots below are from a file processed by Luisa on the grid, you can get it via dirac:

$ dirac-dms-get-file /vo.cta.in2p3.fr/MC/PROD5/Paranal/gamma-diffuse/ctapipe-process/0000/Data/000xxx/gamma_20deg_0deg_run50___cta-prod5-paranal_desert-2147m-Paranal-dark_cone10.DL1.h5

Additional context
Add any other context about the problem here.