@bernardomattiucci I think you need to read up on heat creep in filament as it sounds like that is your issue.
Basically, over time heat creeps up the filament in the extruder. When the filament gets warm, it expands a little. If it expands too much, or even worse melts in the heatbreak, it can cause friction in the heatbreak and so cause a blockage.
In normal printing, you are constantly pushing fresh filament through, so no big issue. When you retract, you pull warm/hot filament back up and so it gets worse. Lots of retraction and travel means lots of time not extruding fresh plastic so it builds up more heat and is more likely to cause a blockage. Cheaper filaments may be more susceptible to this, or are just weaker hence the powerful hemera just strips it when things start getting stuck.
I would check your cooling setup on the hemera. Are you using their standard fan? Is there enough room for airflow around the heatsink? Have you set the motor to the correct current? Is the hotend assembled correctly, with suitable thermal paste, clearance to the heaterblock etc. Have you got a silicone sock over the heaterblock?