Xfinity Stream app 8.15.1.3747 on FireStick - Audio/Video sync issue & Mini-Guide bug [BOTH FIXED]

I had version 8.15.1.3747 on my Amazon FireStick (3rd Gen) and I couldn't stand the bugs anymore.  This is how I fixed it:  I finally uninstalled the Amazon Store's Xfinity Stream app version 8.15.1.3747 and downgraded to the Xfinity Stream app TV/FireStick version 8.12.0.2517 by side-loading it.

It's VERY IMPORTANT you download the TV/FireStick version and NOT the one for mobile devices.  (Yes, apparently there are 2 different .apk files.  The mobile device version won't work properly on your TV.)

There are many tutorials on YouTube for "How to side-load apps on the FireStick" if you need help.  You cannot use the Amazon Store to download older versions; they must be side-loaded!)

After you successfully installed version 8.12.0.2517 by side-loading, make sure you change the following settings:

Go to the FireStick's Settings -> Applications -> Appstore -> "Automatic Updates": OFF

Settings -> Display & Sounds -> Display -> "Match Original Frame Rate": OFF

Settings -> Display & Sounds -> Audio -> (if "Best Available" is already selected) set to "PCM" or "Dolby Digital Plus" or "Dolby Digital")

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Issue #1: The audio/video sync issues have persisted since about version 8.13 or 8.14 (I don't remember which versions caused this issue first, but this latest version of 8.15.1.3747 caused it AGAIN!) -- I could only watch a channel for anywhere from 15-45 minutes or so, then the audio and closed captioning would match, but the video would be delayed.  The only fix was to exit the channel back to the "Main Guide" screen, and then re-select the channel again.  Having to repeat this process every 15-45 minutes made watching TV for any extended period of time aggravating and very, very frustrating.  Also, it's worth noting that every recent update since about version 8.13 would either fix this issue or cause it to return.  Each update in-between 8.13.x.xxxx and 8.15.1.3747 was a 50/50 gamble.  Now that I am running the older 8.12.0.2517 version, everything has been fine.

Issue #2: The "Mini-Guide" (that displays on the right-side of the TV) was also completely messed up on 8.15.1.3747.  Any time you press the "Right Arrow Button" on your Amazon FireStick remote, it should select the Mini-Guide and the corresponding channel you are currently watching.  The problem was that the Mini-Guide would display, but it wouldn't be on the correct channel.  After opening the Mini-Guide with the "Right Arrow Button" on the remote, I would then have to hold the "Down Arrow Button" to get the channel list to scroll from the top...  EVERY TIME!  I don't know how else to explain it other than that way.  There was no fix either.

And before anyone gives me the usual responses: Clearing Cache & Data did not fix either issue.  Changing my TV's Audio/Display Settings did not either.  I've determined these are "Xfinity Stream app 8.15.1.3747" bugs.

THE ONLY FIX was to uninstall the Xfinity Strram app completely.  Then downgrade to the Xfinity Stream app TV/FireStick version 8.12.0.2517 -- if anyone else decides to do this, MAKE SURE you search for the TV/FireStick version .apk and NOT the .apk for mobile devices.  Ask Google ai how to side-load .apk files onto your FireStick if you need help.  Also make sure you turn off Auto Updates in the FireStick Settings, or else it will overwrite it at some point and you'll have to repeat the downgrade process.

I hope this helps people out there dealing with the same issues I had.  I've been watching TV just fine for hours now on 8.12.0.2517 with no audio/video sync issues, and the Mini-Guide is back to normal.