Commercial Fixed Wing
Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Confusion; Communication Breakdown; Situational Awareness
ATC Issue All Types; Deviation / Discrepancy - Procedural Clearance; Ground Incursion Taxiway
Flight Crew Requested ATC Assistance / Clarification
Human Factors
Taxiing out from spot. Ground controller stated 'After the heavy join Lima Zulu bridge to 18L'.  As trained; the FO (First Officer) read back the clearance and stated the clearance to the Captain. As the Captain; I stated the clearance back to the FO. As we proceeded to Lima taxiway the Ground Controller stated ' Aircraft X where are you going?'  The FO stated you ' said join Lima...' upon to which I said to the FO that's what the Controller said.  After being felt like we made a mistake. The FO and myself noticed this Controller made a few more clearance errors that needed to be corrected. The FO and I (Captain) discussed the event later on. Suggestions from our side that might have caused the event is that:1) The Controller might have been tired at the end of their shift. 2) Controller had grown complacent and had expectation bias of what Company operated aircraft doing what they 'normally' do.       From the crew side of the event; we should have questioned the clearance since it was an abnormal clearance.  Bring back pre- COVID staffing to ATC so proper rest can be had for ATC personnel.
Air Carrier flight crew reported incorrect taxi clearance was issued by ATC and cited possible staffing issues at the controlling facility as a contributing factor.