Steps to reproduce:

1. Create a new map.
2. Turn on "Expand macros".
3. Add a new map element.
4. Edit the map element.
5. Set type to host.
6. Select a host.
7. Use macro {HOST.HOST} as label.
8. Click apply.

Result:
Zabbix throws the error "cannot expand macros".
Expected:
The value of macro {HOST.HOST}