Your version of Ladybug Tools is not compatible with OpenStudio 3.1. You are not using the latest Legacy plugins (LB 0.0.69 and HB 0.0.66 - see Ladybug Tools | Food4Rhino), which is necessary if you want to use the Legacy versions next to the new LBT versions.
See this thread for further information (which links to others):
Also check the compatibility matrix to see which version is compatible with what:
What threads are you referring to?