I have a funny bug at NGO right now. For some player planes (only non connection planes) the time of the handling timer does not change after accepting it for landing. Don’t know how to explain it better… 
Maybe the screenshots will help:
Here the A380 is landing but still the initial “accept for landing” 5 minute timer is running down:
At the gate almost no time is left:
Only if I go back to main menu and then and repopen the airport the timer will change to the correct handling timer:
I had that twice within the last 10 minutes…