Steps to reproduce:

1. Create Host group 1
2. Create Host group 2
3. Add Host 1 in BOTH Host groups
4. Add Host 2 in Host group 2
5. Create User group 1 with host group acl on Host group 1 AND Host group 2 w/o tag filter.
6. Create User group 2 with host group acl on Host group 1 AND tag filter with tag name and action
7. Add user in BOTH User groups

Result:
User cannot see problems w/o tags or with different tags on Host 1

User cannot see any problems on Host 2 (does NOT belong to Host group 1)
Expected:
User can see all problems on Host 1 and Host 2. I thought User groups are inclusive and not exclusive.