Since the latest update there is all sorts of weirdness going on in the Pokedex - here’s a few anomalies I’ve spotted… but there are probably lots of others…
Shiny Alolan Rattata. I think this is the first time we’ve been able to view a shiny that hasn’t even been released. I can see shiny Alolan Raichu and Marowak… but at least it is possible to catch them.
Not that weird, honestly. Seeing the Shiny Form of Alolan-Kanto Pokemon has always been kind of a thing since Alolan Raichu was first released this last summer.
As for Spinda, it was leaked months ago that it would be getting up to 20 forms total.
You should go check out the Deoxys entry, assuming you’ve caught one before. You can see all the forms, even the ones you haven’t caught yet. Giratina also has another form slot, although it kind of doesn’t display correctly.
That’s been here since the Alolans have been released. Shiny Alolan Raichu was already in the Dex before Alolan Raichu’s shiny was released. Same with Alolan Marowak’s shiny. Other Shiny Alolans you can view in the Dex right now, even though the shiny hasn’t been released, are Rattata, Raticate, Sandshrew, Sandslash, Geodude, Graveler, Golem, Grimer and Muk. And they are viewable since the shiny release of the normal variant.