my Hue Hub stopping responding to STv2 yesterday and looks like from reading the last thing i can try is uninstall the lights and reset everything again from scratch.
i also received an email about an update coming out on the 21st and hoping this will help with issues and not create new ones.
An update is available for your SmartThings Hub. Between 8:00 am and 12:00 pm Pacific Time on Thursday (1/21), we will be automatically updating your Hub to the latest and greatest version. The update includes improvements to LAN-based device discovery, Hub connectivity, security, live streaming, and Z-Wave device removal.
The update is expected to take less than 10 minutes, during which time your Hub will temporarily go offline.