Phase not working when Fixtures selected via Group preset. Why?

Take a look at selection grid and learn how that works.

And sorry for not explaining it further. But selection grid defines how fixtures handle phase for example.

So Not sure if this is your exact issue since you did not explain how it was not working but here is my best guess, as it seems to work as it should.

Here I have three Groups:

1. 1 thru 10
2. 10 thru 1
3. 1 thru 10 wings 2

If you look at these groups on the Selection Grid they display as follows:

1. 
2. 
3. This is a graphical z-fighting bug, 1, and 10 occupy the same space, 2 and 9, 3 and 8, and so on.

Now when you apply a range on the current selection it always goes from left to right on the selection grid (at least on the x-axis)

Using Dimmer as an example typing at 0 thru 100 on each group would look like this:

The exact same principle works with other layers such as Phase. they apply to the selection order (or selection grid) from left to right.

And you can see this on the phase layer of the Fixture Sheet, This is Group 3 then Phase 0 through 360:

The thing that sometimes throws people off is that the selection order is ONLY the order the fixtures are selected not how the values are interpreted. If I applied 0 thru 360 to Group 3 then I select Group 1, nothing will happen on stage, but the selection order will change leaving the values as they were.

Again for illustration using the Dimmer, this is the selection grid after Group 3, then At 0 thru 100 then Group 1

Notice the selection order changed but the values in the programmer did not. In order to have the values change you would need to call the range values onto the new selection.

I hope this makes sense, and is actually your issue, again more information would be required to say Why it isn't working the way you expect.