well it's clearlt under extrusion.

Could be many things, but with a longish bowden tube, it might simply be the extruder is struggling to push the filament through. At a certain height the angle of the tube changes and it suddenly starts getting through a lot easier.

Could have also been a dodgy patch of filament - but my money is on it just not beiung able to push enough filament through the tube - did you hear any 'clicking' during the print ?

Depending on what type extruder it is - sometimes you can tighten them up so they push through any tight spots.

Regardless of this print - converting the machine to a direct drive extruder would be the first thing I'd do.
Hell I'd have dne it during the construction.
There is no logical reason for the ender 5 to use a bowden extruder other than laziness on creality's part.