I am having the same issue. I have a variable schedule and LOVED the sleep function under the clock app; this has now been changed and is located under the health app and it takes several steps to update. Once the alarm is set under the sleep function in the health app, it can be viewed under the clock app. It appears it can be edited this way but it does not save. I have now been late to work all week because the app is not working.
As a side note, I prefer the sleep function to alarm because the alarms are more pleasant. Hoping they switch this back.