Morphing problem in Harmony 12

I’ve got a problem where my morphing doesn’t seem to follow my pencil hinting and creates weird lines.

Note that I duplicated my first drawing to create the second one, then I tweaked it with the contour editor to keep the same number of points.

Here is some screenshots :

I followed these tutorials and didn’t see anything that could help further than what I already have done :

Any help appreciated, thanks!

I also tried converting the pencil stroke to a brush one with better overall morphing but then the stroke change width during the transition. And I’d prefer using pencil strokes to be able to easily tweak the design even with the morphing done.
It seems that while being more advanced, Harmony seems less predictable than After Effects’s shapes morphing, am I right ?