Missing base game worlds

Product: The Sims 4
Platform:PC
Which language are you playing the game in? English
How often does the bug occur? Every time (100%)
What expansions, game packs, and stuff packs do you have installed? City Living, Get to Work, Vampires, Holiday Celebration Pack
Steps: How can we find the bug ourselves? 1. Run Sims 4 2. Load game (have tried on my two saved games) OR start new game 3. Available worlds are: Magnolia Promenade, Forgotten Hollow, San Myshuno. (plus, on loading existing game, Windenburg world appears but is correctly locked). I don't see any of the base game worlds -- Oasis Springs, Willow Creek, or Newcrest.
What happens when the bug occurs? The three worlds from the base game are missing: Oasis Springs, Willow Creek, or Newcrest.
What do you expect to see? Expect to see Oasis Springs, Willow Creek, or Newcrest, when loading a game.
Have you installed any customization with the game, e.g. Custom Content or Mods? Never used.
Did this issue appear after a specific patch or change you made to your system? Yes
Please describe the patch or change you made. Happened in a recent auto-installed patch as was working on September 10th and wasn't working by September 15th.

‌