Just to add to the noise, the Temple in my city is also bugged in the same way. It immediately showed as upgraded to level 5 when I logged in shortly after the update, with all monks unlocked except for Chan. The people in my town have yet to see any monks, and also the population of our city did not change from before the update despite the Temple saying it was now level 5 rather than the prior level 3. I’m guessing that should have added 10k or so to our population.
We can donate the Potions of Return to the Temple for the next upgrade but I’m rather hesitant to do so for fear the Temple may be rolled back to level 3 and delete our donations – which realistically it should be, since we didn’t put in any of the work to get from level 3 to 5 :)
I’ve also heard a number of others express this in chat, so I believe it’s a very common issue despite the relatively few posts in the forums.
If needed, my town’s name is New Aries. Thank you for listening Lamatiel :)