First off Why did you glass bed a new rifle, you may have fixed an issue tat didn't exist
Have You tried running some fired or dummy rounds trough your action and see if it was happing with them?
If it is happing at home with the dummy rounds watch and try and see what could be causing it
Then take the stock off and run the dummy rounds trough and see if it still does it, if it doesnt with the stock off then the stock is the issue.