i dont know the issue tbh but.
Mi Flash to return to CN
(
https://www.xiaomiflash.com/downloads/MiFlash20181115.zip)
unzip password is xiaomiflash.com
and download and unzip the folder inside the 2 files from here: (
https://bigota.d.miui.com/V12.5.7.0...ACNXM_20210519.0000.00_11.0_cn_14a7f64ead.tgz)
(don't choose to Clean+Lock | Choose only Clean on the bottom right)
Flash.... and it goes into CN Version
(If you have a ERROR in then, don't worry its because it didnt locked your bootloader)
1 - Download TWRP (
https://androidfilehost.com/?fid=14943124697586348269)
2 - Boot into TWRP via fastboot (
fastboot boot twrp.img)
3 - Option Inject TWRP on Advanced
4 - Format Data (don't reboot after)
5 - Flash ROM
6 - Go make lunch until it gets ready xD
This worked for me, went back and now it decrypts.
The differences between this and what i did before was that i didnt injected anything and i rebooted after format so one of these were the problem.