Without seeing the van, im gathering that the dealer is forcing the van to regen. If this is the case and the ash accumulation in the dpf is so bad, well its pointless what they are doing then. You need to get live data from diagnosics see how bad the back pressure is in the exhaust/dpf. A clean dfp should be between 5-14 m/bars at ideal and read aboit 60 mbars pressure at round 3k rpm. Imo your van needs a proper dpf clean aka dpf cleaning fluid sprayed into the dpf through the pressure hose..
I would advise bringing the van to a trustworthy tec mechanic to help with this issue other than main dealers because this will cause more problems around the engine most likely when your warranty runs out!🤦🏼♂️