That was a surprise. I had heard that China Anne McClain was leaving the series during the season, so I was expecting what looked to have happened at the end of the previous episode. I hadn't heard boo about
Jennifer being recast
. Leaks happen all the time; that it didn't this time was remarkable.
This week's episode was titled "Theseus's Ship" but they never referenced it. The creators just assumed that if you were interested you could do the research on your own if you didn't know the reference. You can also go to the season finale of WandaVision to hear a full discussion of that.