@Makertech ok, that makes more sense. My question was due to not seeing how this could happen for any normal reason. My issue was on a single extruder, but i believe that the pauses could have been during layer-switches, if you see my picture the blobs are mostly on the same place and i had the option to switch layer at the hardest edge selected. Could it be that the temperature have dropped slightly on the hotend so that the printer pauses to get the heat up again before starting on the next layer?

@Makertech So the stopping for a couple of seconds while pushing out filamend and then continuing moving is due to extrusion hardware issues? Is there some kind of sensor that feels that the extruder cannot push the filament and then the hotend does not move? Because that is what happened during a couple of my prints until it stopped happening after it hung up and rebooted.

I had the same issue, using SD card. But it fixed itself midprint. Attached is the picture of that print. You can see where it paused and caused blobs to the left of in the picture, then it locked up which made the printer to reboot before resume, Blob from that can be seen next to the bridging section. After that the print finished the last part perfectly and I haven't had the issue at all.

I did some investigation on this. From what i could feel the PTFE-tube was pushed all the way in, there was a distinct stop. However i found out that the PTFE-tube was cut at a slight angle, this could possibly have led to some leakage outside the tube which caused the small blob to form. I cut the PTFE tube straight with a razor and the unload after that worked great.

I had the same issue on my first prints. Then i printed a temp-tower for another brand of PLA and the printer hung high up in the tower. It proceeded after a pause, which caused it to reboot, since then, i haven't had that issue at all. I have printed in lower temperatures, since then, which is what looked best on my temptower, but it seems strange that it should have anything to do with the issue.

Guillaume, thank you! Your link however does not seem to work.

I had issues with one of the fanducts extruding slightly below the extruder at first at one corner. This led to my first prints getting shifts, first model came loose, second model shifted the flexible plate. U used a hobby-knife to modify the slots slightly where the duct is attached to the fan and the problem dissapeared. It was just 0.2 mm or something like that, but that was enough for it to catch the model and shift the plate. So make sure you don't have the same issue.

Here it is for you all to enjoy. https://www.thingiverse.com/thing:3557110 Might do something for the 2040 extrusions at a later date.

I ended up modelling an endcap myself. Doing testprints and will share when i am satisfied with the result.

I had the same issue first. I found out that one of the small metal parts that goes up from where you attach the belt was a little bit bent and dragged the side of the gap in the 2020 extrusion. I bent it slightly with a pair of pliers and the problem went away.