also, an odd thing i noticed was that i saw red in it's name; first i thought that it's a boss and not a shiny after all, but nope, it sparkles and the red text actually says Legendary! wow! ... wait what?
well anyways, TLDR: the spawn rates seem to be way too high! maybe i was just lucky to get those Charizards to spawn but in no way should they spawn so easily with mega stones! or i was again just lucky..
The spawn rates for mega bosses and Gen 1 starters are pretty high currently. That is probably so everyone can easily get their hands on megas and try them out. They will most likely return to normal/not as high with one of the future updates.
Boss charizard spawn rate being too high is already documented in the upcoming changes. Gonna be dropped to a lower amount in the future.
Although, dislike that they're gonna change bossSpawnRate to bossSpawnTicks, since that's how legendaries are handled, and if you've been on a server when there ain't much people, you can spawn a lot of legendaries pretty fast, and capture them all.
Do that for bosses and people who come on add odd times will have an unfair advantage as they'll be the only ones spawning bosses.