Adam’s device type handler is designed to match the manufacturer’s original intention, of having the Osram switch directly control other zigbee devices. That’s why you’re having a problem.
Because SmartThings is a multiprotocol platform, it allows for some devices to be set up as what smartthings calls a “button controller.” In a Device set up as a button controller, pressing a button on the device just sends a message to the hub. Then you have a smartapp on the hub which captures that message and sends another message out to a different device. In this way, you can use devices of completely different protocols that normally cannot talk to each other, which is the situation you have because you have one zigbee device and 1 zwave device.
The first device type handler for the Osram switch which was created by a community member did treat that switch as a button controller. It also had an accompanying smartapp to process the messages. However, Adam wanted to go back to the original design features of the Osram switch and have it talk directly to other zigbee devices without going through the hub. Which is a little bit faster and can run locally, but doesn’t meet every use case.
One of the most versatile things about SmartThings is that it allows each individual customer to assign the device type handler that they want their own device to use. If you use Adam’s, you are using the Osram switch purely as a zigbee device.
In your case, however, you want to be able to use the Osram switch as a button controller. So you need the original community – created device type handler by @Motley for the Osram switch, which treats it as a button controller and will let you control Z wave devices by using the hub as a middleman. 