I have a Longer lk5 pro and for a few weeks I have been experiencing some printing defects: the first layers develop malformations only on some edges of the print, that I can not fix by changing the temperature,cleaning the nozzle, changing the speed or adjusting the leveling of the bed. I also tried to change the filament with a new one, the result is the same.
Once the first layers have been printed the next layers are perfect. I attach photos: