It is important to understand how to edit repeat shifts correctly to ensure that your scheduled shifts do not get accidentally deleted.
To keep all shifts on the schedule, you must edit the shift on the correct date the repeated shift starts.
For example, if you create a shift that starts on May 1st, and repeats daily up until May 30th, you would need to edit the May 1st shift to ensure changes are made for all shifts from May 1st - to May 30th.
If you click on the shift that is on May 15th, for example, and go ahead and edit, the shifts from May 1st-14th would be deleted - UNLESS you change the shift start/end date during editing.
Please watch this video for clarification.
How to edit repeat shifts