You are correct. There should be a "vacuum effect".
Check the fuel pump, filter accumulator array and make sure there is no leak anywhere. You will need to get under the car on a hoist or with it on ramps to check it with the engine running.
When you changed the fuel accumulator you possibly may have disturbed something else.
Did you change the filter at the same time? Did you use new copper crush washers on the filter connection?

Or as mentioned - your check pressure valve may have gone bad.