Steps to reproduce:

1. Create a new host, then create a map with element type "host" using this newly created host;
2. Create a new map with the element type "Map" and link the previously created map as its submap;
3. Active a Maintenance period for the newly created host;

Result:
The map doesn't display "1 host in maintenance" as it did before version 6.0.29. This issue started occurring after the 6.0.29 update.
Expected:
Make it show "1 host in maintenance" like it did in previous versions.