I had checked all of the categories and found only the one example ofa 'larger' tag. Creating and using an empty library gave no different result.
To correct this I had to remove Calibre entirely, CrapClean, reboot, and reinstall Calibre (0.8.48). Even thenthe initial Tag Browser position on first launch was as previously described, but I was now able to grab the resizer and make an adjustment. Added all my libraries back and now things seem 'normal'.