Steps to reproduce:

1. Open host edit form
2. Create value map "value map 1"
3. Update host
4. Re open host edit form
5. Open value map "value map 1" for editing and change name to "value map 2"
6. Update host

Result:
Host contains two value maps "value map 1" and "value map 2". Also when updating error is shown:

Invalid parameter "/2": value (valuemapid)=(1322) already exists.

Expected:
No errors. Host form updated.