My dog has always been afraid of other dogs. However, he is not unmanageable even in the presence of another dog. If that dog is allowed in his space (I've had other irresponsible owners let their dog run up to him loose and he has been attacked)...
...If a dog is allowed to run up and be in his face it may start something. Although even provoked, he has never bitten another dog. Does this disqualify him as a service animal?
A provoked Service Dog may be allowed to react but the handler must be able to take effective control over them. Instigating a fight with a dog that just gets in his face is not really acceptable behavior either.
it doesn’t 100% disqualify him as a Service Animal, but it’s absolutely something to look out for and maybe speak to a trainer about.