try printing at either a slower speed or a higher temperature.
Or both :-)

I'd go for too low printing temp.
Plus pet-g printed cool is actually weaker than pla and has layer seperation issues if you flex it.
Actually had a piece of pet-g flake off and hit me in the face. The same part in pla flexes better and doesn't shoot bits at me.
So next time I use the pet-g I will be upping the printing temp by at least 15c.