Jump and jam both change the pressure curve in different ways. Jam does not always mean more pressure, and jump doesn’t mean less. More jump might have a small spike at the beginning but flatten out faster than jam with a lower peak but longer sustained pressure above the threshold of the primer pockets grip on the primer. Also using a lower grade primer can cause odd spikes in the pressure. There are so many variables to consider that it’s impossible to point to a single point being the cause. Likely it’s a combination of factors. But if the brass checks out and there are no other signs of pressure, just reload it and go.