Yep, happened to me a couple of years ago, flying out of Bangkok for Dubai, B747-200 frieghter.
When we tried to get clearance to enter Indian airspace, you all know how difficult that can be, we were told our overfly clearance number was not valid.
Finally, at the last minute (literally), we started into a very big LH orbit, with one flightcrew guy talking to the Indian controllers (?), another getting clearance from the current controller to do the orbit with the associated estimates etc, they required, and the FE (thank heavens we had one!), on the HF phone patch to company operations to get this sorted - which they did about half way into out second orbit.
Indian overfly authorized, we then pressed on, but the fuel reserves were severely affected.
PS: The overfly authority number was not changed because it was, in fact OK, the controllers just got it wrong, somehow!
Cheers, FD
