Fibaro switch connected in old app but not connected in new app st

Hi there, a couple of years ago I started using ST new. Gradually i expanded the number of lamps, switches and sensors. About a year ago I installed the old app just out of curiosity. Recently I lost connection with my Fibaro double switch, just one channel. The strang thing here is that I have no problems problems connecting with my old ST app. Of course I can reconnect most likely but I hate having to open wall mounts all the time where as it seems to be a software bug. Any help would be appreciated.