You may need to change your battery.
Your dwell could be too low.
The marker could be over or under lubricated, or your lubricant may not be best suited to the conditions you are playing in.
If you have an aftermarket board, it would almost certainly have an anti bolt stick setting that adds dwell to your first shot to overcome bolt stick. If so, the value of the adjustment for this feature could be raised.
O-rings on or in contact with the bolt could be worn and need replacing.
A bolt modified to accept the insertion of a spring at the rear can help to minimise or eliminate bolt stick.