Since it went away by itself, I would check, if sensor wires (end stop switches, temp sensor wires)and the hot end wires overlap. Maybe the current in the hot end wires causes some kind of interference with sensor signals.
I tried different temperatures, speeds and layer thicknesses. No luck. I noticed that the messiness starts at a spot where the z distance varies and I think that might have to do with a "flat tire" on one of my Rostock Max V2 cheapskates. I think I tightened it too much and one of the bearing sleeves got "sticky". I loosened the tension and the stickiness went away. I am now trying to see, if the prints in that area will get smoother.
i find with certain poor quality filament the moisture content is very high, this will steam and pop a lot, but if you do want to use it,i find if i slow down the print speed to 20% and heat up to 240 and walk away... tbh rather get some pla.