Issue with maximising window command

I just noticed a bug with the maximizing command. I created this one to maximize the Excel window when it's active, and besides having to switch back and forth to make it work, it worked just fine. But for a couple of days, it will no longer work.
I also tried to delete the whole Excel command and add it back in, but it didn't help.
Is this a bug, or do I do something wrong?
Here is the command I created: