The vaccum isn’t supposed to run the entire time. If you are seeing delamination on the models there are a few reasons or items to check for…
That you powder settings are correct. (i.e. correct powder/binder type).
Make sure your cleaning station is actually allowing for your cleaning solution to shoot out correctly.
Check your printhead life… generally don’t go past 1000ml on clear and 5ooml on colors.
Check to make sure your heater is working correctly to create a consistent environment.
Check your snowplows, if they are grooved this can cause powder to not spread correctly.
Binder expiration… there are times that if the binder is close to expiring then you might want to clear that out.
These are just a few items off the top of my head. If nothing else call your service provider to have them come take a look.