There are different therapeutic structures. Not all therapists have to abide by the same rules. For example, my husband and I have received therapy through the veteran's admin & there are certain functions at which we run into former therapists. It's perfectly okay, within the military 'family'.

passionfruit, perhaps sending your former therapist a message would be appropriate. If she doesn't respond, or if she explains that she cannot ethically communicate with you, don't take it personally because it's not about you - it's about her job.