Apparently, it's a bug. There's a patch that fixes it on the Reborn server on Discord.
Edit: You can also download patch 2 for the game to fix several bugs and glitches. It's on the development blog in the Rejuvenation section.
I can confirm this. The evolution method is almost the same as in the mainline games: let Yamask take 49 or more HP damage without fainting while in the Wispy Ruins.
Have you been to Axis High University already? It's north from the Central Building in GDC. Erin should be there and a little cutscene will play out. After that, go left to the District of Hope and go north to find the hospital.
If you walk in a straight line upwards starting from the rock climb spot, you should come across a small river. Cross it with surf and keep walking south until you see a second rock climb spot. Climb it and there will be a code panel and trap door nearby.
Both. I'm continuing my save file from V12, but I also want to see all the changes and newly available Gen 8 Pokémon. I'll probably attempt a Grass monotype challenge and choose Grookey(with Grassy Surge of course) as my starter.
Also, there was a package for Rhodea in Zone Zero, but she didn't seem too happy with it.
Did you find the hidden sentence underneath the GIF? It sounds rather sinister.