I didnt manage to fully fix the problem like how you wanted it to work. but no matter the values added, if its set to health_max it always outright kills. if i just set it to health/5 she just drops down to 5hp every time. no matter what i tried with the values health_max is a death sentence.
Edit: Without the entire line that messes with health. they still drop down to 6hp out of 100. so something else may be tied into this issue.