The popularity of Pokemon GO is not as high as when the game was released, but it is still one of the most profitable applications on the market. This title is still being developed, also in terms of security. Game developers want to secure their app against the use of modified versions of the code, which made it difficult to use Pokemon GO on custom roms. It seemed impossible for any player to be blocked on their account just because of the brand of phone they are using. It turns out that such situations take place and, what's more, it begins to happen more often.
On many forums regarding the game and on Reddit appeared large number of posts indicating that players have received bans on their account despite complying with all regulations. It turns out that all these problems apply to people who have Xiaomi phones. Pokemon GO blocks access to the game for Xiaomi users due to some MIUI functions, which the application considers dangerous or also allowing cheating in the game itself, hence some users were accidentally automatically banned and they can't use the application with their accounts. For now, Niantic has not taken a position on this matter, but certainly the company will want to solve this problem in order not to lose some of its players.