So I feel really lucky right now but I believe I found a glitch. I waited until after the E4 to go do the mission for the shiny Dieno. I was going to try and get good IV’s so I constantly reset. However a couple resets in I get the Entei encounter instead of the dieno, and because its a forced shiny Entei was shiny. Just something I found interesting.
Yeah,the roaming legendaries can replace every ecounter! that one is a good way to encounter a shiny version of those legendaries 