Could you please share the .3mf file used?
It is recommended to double-check that you are using the PETG Basic profile and not the PETG-HF filament profile.
The PETG-HF filament profile has faster settings and could cause this problem with regular PETG Basic.
it is also recommended to check the volumetric speed limitation in your filament profile, which would be 9 for PETG Basic.