See every powder charge you seat a bullet over.
This!!!!
The OP needs to be checking each case for an appropriate powder charge.
If loading on a single stage press and using a loading block for charging cases, check the powder charge in each case to make sure it is about the same level as the others.
If loading on a turret or progressive, have some method of checking the powder level in each case after the powder measure. This can be a visual check or one of several powder cop dies on the market. This will verify the powder charge is throwing approximately the correct charge.
If you get a jam/stoppage, remove all cases around the powder measure from the press to make sure you do not send a case empty of powder to the bullet seating station.
The best system is to never assume powder is in the case. Check, then check again, and finally verify that the appropriate powder charge has been charged to the case.
Squiibs are not something to be taken lightly.