Question Roland GR-420 : perforated cut - horizontal lines differ from vertical

Hello
I am trying to find good settings for perforated cut of the baking film (only the film, not the adhesive upper layer) of Siser ColorPrint Media.
Using ZEC-3075 blade with the fin.
I noticed that whatever settings I supply - the horizontal lines seem to be getting cut "more". For instance, I have found the following combination to get me easily separatable horizontal lines (full cut - 5mm, half cut 4mm). However, while the horizontal lines are easy to disengage after the cut - the vertical lines are far from it. If I decrease the bridges from 4mm to 3mm in the settings - the horizontal lines will start disengaging already during media feeding while cutting but the vertical lines will "improve".

What does that mean? Which setting can influence this behavior? I tried to lower the speed, play with the full cut force, vacuum settings. But the vertical lines always seem to receive "less" cut.

Any ideas will be appreciated

thanks