Ghost suppressor issue

I have just found after many boxes of ammo that my ghost suppressor on my 308 bergara takedown stainless synthetic 16.5 that when we take the suppressor off the gun groups so well at 100y that there going through each other my friend has had the exact same issues with his one who else has had accuracy issues with the ghost suppressor The gun with the suppressor on wood group wellish for a couple of bullets then be high 30 cm group up there then go back to another spot group there one fly off high again 30 cm both our guns with the suppressors have done this I'm just getting told now that there sht suppressors and that the gun shops know this

so... groups well without the suppressor and then all over the place with the suppressor on?
Bergara ba-13 rifle?
as far as i know the suppressor is rubbish just like hushpower

I had a Bergara same model. I projectile was "clipping" suppressor on way out. re-threading solved the issue in my case. Was not a suppressor issue