Did you try the drivers from @markus?
He left developing for HE some time ago, but I could swear his driver had the ability to enable and disable decoupled mode for the buttons. In fact, we worked on adding support for the D1 models at one point and I'm sure it was in there, because I didn't even realise it was a feature until then. Oh, nuts - is it a H1 you're using? 
My only other advice would be to ditch the combined switch and button setup entirely. I found them to be an absolute nightmare. I now use WXKG06LM and WXKG07LM wireless buttons with my drivers and Zigbee2MQTT routing to control small relay switches in the back boxes, many of which are supported by Hubitat directly.
