Nextruder fails to grip a 40D TPU well

As you can see in the video I insert a filament and keep pressing „purge more“ but nothing comes out until I push the filament from the top with my fingers (and afterwards purging works as intended without additional intervention). The filament in the video is Fiberlogy Fiberflex 40D. I never had such issues with this filament on my MK3S+. Does anyone have similar experience? I already tightened the idler screws by 4 turns, but it looks like the plastic part of idler just rests against the metal Nextruder frame. Maybe I should redesign the idler, so the small pulleys can reside closer to the filament feeding gear…