Steps to reproduce:
Create 3 hosts:
-VM01
-VM02
-VM03

On each host we need one item, lets pick system.cpu.load (all of them should use same name)

Put VM01 in maintenance.

Now, create new dashboard.
-Host navigator widget matching on host pattern VM*
-Item value widget: item VM01: CPU load + Override host -> Host navigator widget.

Save the widget/dashboard

Result:

Refresh the page etc: it will pick VM01 it's item by default, whilst its not presented in the Host navigator widget.

Expected:
No VM01 value here... it's hidden by the host navigator widget, so extremely confusing to see it's value in the item value widget.