Steps to reproduce:

1. Create superadmin user
2. Create Read only user
3. Make a hostgroup called:"lots_of_hosts"
4. Add hosts in the hostgroup
5. Create another host group called: "hide"
6. Add hosts in the hostgroup
7. Add tags to the hosts with values
8. Make a dashboard
9. Create a widget on the dashboard eg: host availabillity
10. set exclude host groups to: hide, set tags to the tags you previously created
11. Share dashboard with the read only user
12. Trigger problems to have data on the dashboard
13. For the superadmin only the hosts in the lots_of_hosts hostgroups will be present
14. For the Read only user exclude hostgroups is disregarded and all the host's problems will be present on the dashboard 
15. Give superadmin user to Read only user: hosts disappears from dashboard
16. Revoke superadmin access from read only user: host appears on the dashboard

Result:

For the Read only user exclude hostgroups is disregarded and all the host's problems will be present on the dashboard 

Expected:

Host is supposed to be hidden for both users regardless of user permissions