Eurocopter confirmed there is a problem with the fuel indication and alert system on some EC 135 models.
It comes two weeks after the Police Scotland helicopter crashed into the roof of the bar.
The company's technicians have been carrying out safety checks since Bond Air Services discovered the fault last Wednesday on its North West Air Ambulance in England.
The operator immediately suspended all flights on all 22 of its EC 135s, but many have since been given the all-clear to resume flights.
In an urgent safety notice, Eurocopter has raised concerns the possibility of the aircraft's instruments giving inaccurate fuel readings.
It read: "Eurocopter has been informed by Bond of an issue involving the fuel indication system on one of its EC135 EMS aircraft during normal operation.
"Following this incident, tests performed on EC135 have revealed supply-tank fuel gauging errors on some aircraft.
"The first analysis shows the indication of the fuel quantity in the supply tanks could be overestimated."
The Eurocopter alert was not the first warning about the EC135 because it had previously released a notice regarding the "possible water contamination of the fuel system".
In response to the manufacturer's statement, Bond said: "We understand other operators have since conducted similar tests and found similar problems with their aircraft.
"As soon as we discovered this issue, in line with our commitment to the highest standards of safety, we took the prudent decision to temporarily suspend service operations whilst it conducted checks on our fleet of EC135s.
"The results of these tests were subsequently validated by Eurocopter, and appropriate repairs made before returning the aircraft to service."