There is a bug when you try to create dynamic groups using the formula wizard. When you try to create a group an and us the Insert OR Group everything look fine until your select OK and then it changes your formula from a pipe (for OR) to an AND.
Here is the work around from Microsoft.
This is a known issue that we are tracking. As a work around in your case – after you add ‘Windows Operating System’ to the formula grid, right click on ‘AND group for Windows Operating System’ and select ‘Switch to Or group’.