T-Mobile-YouTube incorrectly throttles 1080p high bandwidth videos on youtube.com in the web browser for ALL T-Mobile customers

wfgarnett3 wrote:
It is not just prepaid - I traveled to multiple stores in the Philadelphia metropolitan area (Levittown/Langhorne, King of Prussia Mall, and Springfield Mall) and the Android display models and the actual employee's personal postpaid Android phone all had the web browswer stuttering.
In addition, I have another phone number that it is AT&T so when I pop that sim card into my Android phone there is no web browswer stuttering.
Can I get some of you to run the test below to see what regions of the country this is happening?
Reply back the area of the country you live in (can list state or region only if you want for privacy), the plan you are on, the Android model phone you are using (please no Apple iPhone users), and state whether is stutters or not in the web browser in step 8 and verify the YouTube app itself in step 14 plays OK.
Thanks for the help everyone!
Testing Steps
1. Verify first that Wi-Fi is OFF on your cell phone - if not turn it off so the top of the screen shows LTE and the cell signal with no Wi-Fi connection.
2. Log into My T-Mobile and if there are video optimizations available (Data Maximizer, Binge On, etc) make sure they are OFF and HD is enabled.
3. Open the web browser on your phone -- Google Chrome or Samsung browser.
4. Type in web address for YouTube (howardforums is not allowing me to type the web address since I am a new poster)
5. Search for Karmin Hello - the first result should have this at the end of the URL: 0_I0DBUA_GI
6. Play the video (ads may play first).
7. As soon as the video starts click the wheel icon (settings) and change quality to 1080p and click "Stats for Nerds" and click OK.
8. The video will either play fine or the video will stutter and freeze throughout.
9. If the video plays fine the Stats for Nerds Connection Speed should be high.
10. If the video stutters the Stats for Nerds Connection Speed should be near 1500 kbps showing the video is being starved for bandwidth.
11. Close web browser.
12. Open YouTube app on phone.
13. Search for same exact video.
14. Play it at 1080p - the video should not stutter at all.

Yes I have done all multiple times, and have no trouble.  From what I remember in that specific thread especially on prepaid plans you are 480 all the time.  Now some employee plans are treated like prepaid plans(even if they are postpaid) from what codes I have seen.  No I do not work with T-Mobile, but the company I have worked for dealt with a lot of carrier plans.

I have an HD plan which I always have on since I got the plan and paid for HD video and never turned them off.  For reference I have the original T-Mobile One Plan with the promotional HD video on all my lines. 

What I think is happening has to do with how T-Mobile checks for tethering and not actually throttling the HD video itself.  T-Mobile plans offer tethering at "3G" speeds unless paying for specific 4G data bundles that offer high speed tethering.  If the network thinks you are tethering you speed will slow down to 3G speeds.  This also happen in certain apps as well.