Unless SmartThings has changed how composite buttons & switches work, they used to show up in groovy apps as both a single device where you can later select which button (or switch) # to use. They would also show up as individual single button (or switch) devices as well.
Try pasting over the button device definition in the HubConnect SmartApp in SmartThings (don't change in Hubitat):
(It's on line 61)
"button": [driver: "Button", selector: "genericButtons", capability: "button", prefGroup: "other", synthetic: false, attr: ["numberOfButtons", "pushed", "held", "doubleTapped", "button", "temperature", "battery"]],
There are some fixes for the ST platform coming in 1.7 and this is one of them.
