Xbox party chat name is different from gamertag

"In 2019, Xbox expanded the range of possible gamertags and languages. Get the details below."

"Suffixes are 4 digits by default, but they depend on how many gamers have chosen that gamertag. For a 12-character gamertag, we’re limited to a 3-digit suffix. For an 11-character gamertag, we’re limited to a 4-digit suffix. For 10 characters, a 5-digit limit, and so on." -- This was the primary change from a few years ago. Which is why your seeing the 4 numbers.

As for exactly why its displaying different I am not sure I could assume it has to display when you are in party or chat to make the distinction between you and someone else with the same name but different Suffix. So maybe Xbox services and systems don't make the discernment you are not currently in the same lobby or party as that person or other people with the same name.

Watching the Beta videos, looked like Xbox Gamertag showed up when you party up, invite chat etc I did not even notice character names but most of the beta I watched was on PS4.

Hi AustinM2,

Thank you for posting on the Xbox forums. I'd be happy to help.

Are you streaming to Twitch directly from the Twitch app on the Xbox? Or are you streaming your Xbox One to your PC through the Xbox Console Companion app? Are you using party chat on the Xbox, or a party through the Xbox Companion app?

What you are describing is by design using the Xbox Live party chats because the servers for the chat are separate from the in-game chat servers. Xbox Live parties effectively mute in-game chat, and mute yourself from in-game chat as well because as I mentioned
previously, party chats and in-game chats run on different servers. Xbox Live parties are more private channels for chatting with friends, so the muting aspect is by design. I believe this is why many Twitch streamers use Discord since you can hear both the
Discord chat and in-game chat at the same time.

Hi Jj_3kc! My name is Ricardo an independent advisor ready to help you with this situation!

Streaming from Xbox will only allow you to stream the Xbox party chat sound, not the in game chat

Some of my friends sound a little different in game chat from party chat on Reach, but the clarity remains the same.