Update 10/5/2019
On 10/5/2019, Niantic officially confirmed that while they are still investigating this glitch, they are rolling back bans and strikes that were wrongfully set against accounts using the Xiaomi 5, and will continue to post updates on their findings.
As an update to our investigation into players using Xiaomi devices, we are continuing to investigate these reports, and revising punishments and Strike counts where appropriate. Thank you for your patience. https://t.co/W8ZYbKYlnR
— Niantic Support (@NianticHelp) October 5, 2019
Update 9/30/2019
9 / 30 / 2019
Niantic Support has officially addressed the issue tied with the Xiaomi 5 and "Game Turbo", the feature that is believed to be tied to the recent waves of bans and warnings, stating that they will supply an update to the situation at a later date.
We’re investigating reports of players getting flagged by our systems while using Xiaomi’s GameTurbo feature, and will share an update as soon as we are able.
— Niantic Support (@NianticHelp) September 30, 2019
Original Post
Players using the Xiaomi 5 series of Smart Phones are reporting random and unwarranted warnings and bans for no apparent reason. Players have flocked to Niantic Support as well as several Social Media outlets voicing their concern for this mysterious epidemic that seems to have the Xiaomi 5 as its correlating factor.
The Xiaomi 5
Official Image of the Xiaomi 5 Plus
Niantic has not yet commented on the situation, leaving many players in the dark with unwarranted strikes against their accounts. The Pokemon Go community has not found a reason/fix for the situation either, leaving the most viable option for anyone using one of these phones simply to not make use of it until a fix is found/issued.