No. This is not supposed to be an early April Fool’s joke.
TTC Customer Service has announced that the 504 King streetcar service western terminus will change on April 1 to its regularly scheduled location at Dufferin Loop. At the same time, the 29/929 Dufferin buses will also return to that loop.
Looking at tracking data (thanks to TransSee), it appears that some but not all 329 Night buses have already resumed their normal route south on Dufferin into Exhibition Place.
Currently, King cars loop from Queen south via Shaw to King, west to Dufferin and north to Queen without serving Dufferin Loop. In the revised routing, cars will operate both ways via Shaw, King and Dufferin to Dufferin Loop as shown below.
Because these are the routes published in the electronic version of schedules (GTFS), tracking apps should correctly predict behaviour of streetcars and buses in this area.