The sounds cause freezing .
Anything that plays any sound causes the phone to freeze.
I have a Mi9 and got 21.1.4 OTA yesterday. Everything seemed fine. I was at work, so besides letting it update, I unlocked it once so YourPhone could connect) I didn't really do anything with it beyond txt'ing. When I left for the day I got in my car and hit to play bluetooth music. A song would play for 2-3 sconds then it'd stop and start back and replay those 2-3 seconds. I assumed something was wrong with bluetooth and listened to the radio on the way home. When I got home I had some minor emergencies to deal with so didn't touch the phone. This morning when coming to work, out of habit, did the same bluetooth music thing with, of course, the same experience. When I got to work, I went ahead and just tried to play music with bluetooh, wifi, and data off. Did the same thing playing through the speakers. Turned back on wifi and tried youtube, and the whole system studdered. I went through a few apps and had the same experience that any time any sound would play, the whole system would studder for a few seconds.
On my computer I downloaded the rom from sourceforge, booted into twrp, connected the usb cable, and did the old
adb push xiaomi.eu_multi_MI9_21.1.14_v12-11.zip /storage
adb shell twrp install /storage/xiaomi.eu_multi_MI9_21.1.14_v12-11.zip
When it finished installing, zero problems with audio.
So either something was off with the OTA or something didn't get completely installed/cleaned on the first install that was corrected by a second one.
Edit: CRAP! Nope, that only worked for awhile. I just took my phone with me into the bathroom to discover the sound problem is back. I cleared dalvik+cache just to check to see if I could get it to work for a short time again, but nope.