Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Flight Crew Last 90 Days 177; Flight Crew Type 915
Aircraft Equipment Problem Less Severe
Flight Crew FLC Overrode Automation; Flight Crew Overcame Equipment Problem
Aircraft; Incorrect / Not Installed / Unavailable Part
The previous week I flew the same [JFUND2] arrival into BOS. The aircraft should cross SEETS intersection at or above FL210. Last week it did not level off as it should have. We had to intervene and manually stop the airplane from descending. We did not have an altitude deviation. Fast forward to today and I am now doing the exact same arrival in a different airplane. This time I am watching intently to see if the aircraft levels as it should. NOPE!!!!! Three miles before SEETS the aircraft was diving below FL210. We were correctly all set up with the airplane in NAV and DES and on glide path. Without aggressively grabbing the airplane and leveling off it would have blown through FL210 by at least 1000 feet; if not more. For the second time; I had to grab the airplane and manually stop it from descending to avoid a major altitude deviation. I believe there is a problem somewhere in the database. It correctly shows on the navigation display and matches with the chart; however the airplane descends as if unaware of an altitude restriction.
A320 Captain reported the aircraft failed to initiate a proper level off  while on the JFUND2 arrival to BOS. Captain stated this is a reoccuring type of event.