I have had trouble lately with this. Although I did get one in July.
In the past I would purchase more that GC was and first swipe GC then use CC for remainder.
Don't ask cashier because they will say that you can't do it at all.
I am going in the next few days to do this again. I think I just tried to use too many cards last time.
Our store all have new registers and I am hoping that they now no longer let this get by.
I love getting my Walgreens MyPoints rewards to use for Disney.
If I try this today, I will repost my results!