Date: 202105
Local time of day: 1801-2400
Location: BOS.Airport, MA
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Parked
Aircraft component: Navigational Equipment and Processing
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; First Officer
Reporter qualification: Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown; Confusion; Troubleshooting
Anomaly: Aircraft Equipment Problem Less Severe; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Automation Air Traffic Control; Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Air Traffic Control Issued Advisory / Alert; Flight Crew Became Reoriented
Contributing factors: Software and Automation; ATC Equipment / Nav Facility / Buildings; Aircraft; Equipment / Tooling
Primary problem: Ambiguous

Narrative: Upon arrival to the aircraft; an ACARS message from our dispatcher was already on the printer asking if we had Revision X to our flight release.  I opened and downloaded the flight release to my iPad.  The release was indeed Revision X.  We replied to the Dispatcher telling him that we did have Rev X onboard.  I never saw the original Rev Y.  When uploading the flight plan to the FMC; the route that loaded was consistent with Rev X.  This route was: BLZZR4 BLZZR BAF Q480 CANDR RAV J64 [...].  I logged into the CPDLC and we received the clearance via CPDLC.  The CPDLC clearance was: 'CLEARED TO ZZZ ARPT BLZZR4 THEN AS FILED. [...]' We accepted the clearance.  From this point the flight progressed normally.  After departure while flying the BLZZR4 departure we were talking to Center; we had not yet reached the BAF waypoint.  The controller gave us a shortcut and cleared us directly to TRIBS intersection.  We couldn't find that fix on the legs page and replied that we were not showing TRIBS on our route.  The controller inquired as to what our route was and I replied with the route that was on our release (noted above).  Controller replied that they had a new route for us and cleared us from our present position direct to TRIBS Q406 BWZ J6 HVQ J78 FAM SGF [...] to ZZZ. We accepted the new clearance; entered it into the FMC; then notified Dispatch via ACARS of our new route.  Later in the flight; while talking to the next Center; the controller notified us of a possible pilot route deviation and gave us a phone number to call Center upon arrival in ZZZ.  The flight continued uneventfully to ZZZ.  Enroute to ZZZ; the Captain and I discussed what possible route deviation could have occurred.  We could only speculate that there was a difference between the flight plan on our Rev 01 Flight Release and the route that Center had cleared us via CPDLC and expected us to fly.  We were confident; however; that we were never off course since both the CPDLC clearance and Rev X flight plan had us flying the BLZZR4 departure; and the shortcut and subsequent reroute issued by Center occurred while we were still on the departure route.  At BAF (Barnes VOR) is where Q480 & Q406 diverge).After the Captain called Center from ZZZ; we suspected that the cause of the problem was that the Rev 01 route wasn't processed by BOS prior to issuing us our CPDLC clearance.  Since both the Rev X route; and the original route that BOS expected us to fly both began with the BLZZR4 departure; we had no idea from the CPDLC clearance of 'CLEARED TO ZZZ ARPT BLZZR4 THEN AS FILED.' that there was any discrepancy.  We are unsure why the updated route wasn't processed by BOS prior to issuing our CPDLC clearance.   Perhaps there is a cut-off time where changes are no longer accepted or processed. Even when being issued a 'Cleared As Filed' CPDLC; listing the entire filed route at the end of the message would be another way to confirm that the ATC facility has the same route as the crew does on their flight release.  In addition; being able to print the entire CPDLC message would also be helpful to not only have a hard copy of the clearance; but also to avoid having to step through multiple pages on the FMC and potentially miss something.  This would be especially helpful when there is an unexpected reroute as part of the CPDLC clearance.




Synopsis: Air Carrier First Officer reported the route received through CPDLC did not mirror the ATC route.