BRAZILIAN_GODESS The EA App budgets extra space for updates, which can make Windows think you don't have enough space on your internal drive. That, in turn, can cause Windows to push data to cloud storage and remove it from your internal drive. This doesn't get reversed when the EA App releases the space again once the update is done.
And again, if you installed Sims 4 in the same location as your user data, that would also explain the issue and be entirely unsurprising.
Neither of these is a flaw with the Sims 4 update. You could argue that the first is bad design of the EA App, but the second is an unfortunate error on the user side.