Steps to reproduce:

1. Create host using some template, for example "Kubernetes nodes"
2. Full clone host, unlink "Kubernetes nodes" and add "Kubernetes cluster" (without saving between actions)
3. Change host name, save

Result:

Expected:
Newly cloned host has no history and if template unlinked, any new template should be attached, even it has some duplicate keys with previous template.

Error message should give some help, not just "something impossible/incredible/unbelievable happened".