Does a girl remain intentionally broken from her fast, despite not remembering breaking it, and her being afflicted with obsessive-compulsive disorder which causes forgetfulness?

If you do not remember that you broke your fast in Ramadan (definition), then doubt after finishing an act of worship is a waswasah (whispering) that should be disregarded, and the act of worship is valid. Sheikh Ibn Uthaymeen mentioned that doubt after completing an act of worship does not affect it, and that one who experiences frequent doubts should cast them aside and pay no attention to them because they are waswasah. Therefore, do not pay attention to the whisperings of Satan, and the best cure is to frequently remember Allah the Almighty, seek refuge in Him from Satan, and turn away from these whisperings.