Reordering servers sometimes isn't possible

### Nova version

v2.0.1

### Observed behavior

title

### Expected behavior

it should work

### Steps to reproduce

1. add new servers
2. try to move those new servers around
3. apparently fails

### Additional information

a few people reported this, still need to try to reproduce

### Is there an existing issue for this?

- [x] I have searched the existing issues