Also mauscarada is my favorite fusion so far!
Having done a large endless run from Friday-today(5k floors), you see a LOTTTT of shiny paradox mons. So don't be too disappointed and def don't hold the run.
So just keep going?
Definitely keep going. There's no telling if the devs will ever change it.
And this weekend alone on my endless run with the 4x shiny charm and shiny weekend I've gone from 5 shiny starters owned to almost 300. Many of them legendaries, and many of them 2nd and 3rd tier shiny.
May as well just keep playing it, a bunch of paradox battles have been shiny too. So if the devs do change it, you'll be able to do another endless run and find them again
Sadly you can’t catch it lol