Error when not filling in non-mandatory Registered sample

[kdp-cloud]

1. Make a sample type with a registered sample attribute or registered sample list attribute but make none of the mandatory.
   

2. Create a sample in that sample type but don't fill in the registered samples
   

3. Try to edit it again. It will return 404

4. Create a second sample but add registered samples this time.
   

5. Try to edit it again. This will work.