I have seen similar behavior using Google Drive File Stream. If another user created a folder in a Team Drive, the new folder wasn’t getting sync’d to my computer. After I browsed to the folder in Google Drive web interface, it triggered a sync in Drive File stream. Working with Google support, I deleted my entire File Stream folder (including offline cache) and re-sync’d the offline folders. The problem appears to have gone away, but I am keeping my eye on it to see if it shows up again. If it shows up again, the problem may be on the Google Drive server side which can also effect other API clients such as Insync.