Huh, I was gonna comment on this and upload my screenshot of a Zangoose when I got home from work. Saw one on my way to work this morning and caught it quickly thinking maybe it's a glitch. Then I saw another one on my nearby list so I took a screenshot in case people thought it was fake. I live in the UK. Hope they do this with all the regional exclusives.
Why is the swapped in one so rare? Zangoose spawned everywhere. But so far I’ve seen 2 Seviper.
One was one of those you waited to long to click on it so when you do it disappears and says error. Saw an Electrike in it so was hoping the Electrike was the older one. Todays just appeared but it wasn’t obtainable since it was at a Pokestop that we only pass doing 20mph plus. Hopefully another one spawns before they seitch again. But it’s a good thing Seviper doesn’t evolve.