Looks like you already have five hundred answers lol, but it almost looks like maybe condensation, it your heating the element in cold weather and it’s humid it can cause bubbles to form. It’s almost like flash streaming the air around the element. Only my opinion. Good luck.
This is a result of prozess by change a layer: stop extrusion-retract-nozzle lifting- extrusion. You need right settings and calibration for Your extruder.
Best regards,
M. Melcher
I use black filament at 228C and natural filament at 223C. I have not used more than just the 2 filaments so far, but based on that, I would guess you need about 225C. Of course, temperature readings differ. I doubt you calibrated your thermistors by sticking a glass thermometer in your hotends and I know I did not do that with mine.
Also, different plastics and colorants will vary the temperature required…
Moisture bubbles maybe?