This is an error I have encountered across windows and Mac versions of Kyno.
When you add folder that is inside google drive sync to Kyno's workspace system and hit drill down it will work for a while. At some point though when you start Kyno the folder will be grayed out as if the folder has been removed. When starting and closing the application it remains in that state even after you check that the folder in finder/explorer is accessible. There is no "try to reconnect" button and closing or opening the application doesn't seem to fix it. Keeping that whole folder structure synced to local doesn't seem to work either.
Sometimes the application will keep the workspace working as intended over multiple system restarts while doing a week of work, but inevitably it will disconnect at some point and the only way to fix it is to add and remove the workspace.