The only parameter I could find to deal with this issue is coasting. After I printed several cubes, I noticed that it created another vertical blob which I couldn’t explain. Using the high-speed camera, I recorded the extrusion using three different coasting parameters (off, 2mm, 8mm) to get a better understanding of what it does.
The problem is, when the extruder stops at the defined coasting value, the movement doesn't continue at the same speed, but it stops for a brief moment before it continues the movement to the end of the perimeter. This was a surprise as I was expecting that the speed won't change until it closes the loop.Coasting feature:
https://www.simplify3d.com/support/prin ... ch-plastic
Coasting will turn off your extruder a short distance before the end of the perimeter to relieve the pressure that is built up within the nozzle. Enable this option and increase the value until you no longer notice a defect appearing at the end of each perimeter when the extruder is coming to a stop. Typically, a coasting distance between 0.2-0.5mm is enough to have a noticeable impact.
Is this how the coasting feature works or is the problem somewhere else? Some other parameter, firmware?