When typing via the in-game chat on Xbox, pressing the 3 lines button on your controller does not automatically send whatever you've written in chat. Instead, you have to press X to send whatever you've written, and the 3 lines button just gets the keyboard off your screen rather than immediately sending whatever you've written. You can also press the 3 lines button again after you've pressed it once/removed the Xbox keyboard from your screen, and this will also send whatever you've written. Additionally, the same exact thing happens when typing via a connected keyboard, you have to hit the enter key twice, or manually press the send button in the bottom right corner of the chat menu with your mouse cursor. 

I can confirm that this never used to be the case for neither controller or keyboard on Xbox, and only became an issue after the performance update for Xbox on October 5th, 2022. 

To reproduce this quickly;

1. Open the in-game chat menu
2. Type something in chat
3. Press the 3 lines button (if you're on controller) or the enter key (if you have a keyboard connected)

Observed Results: Whatever you've written in-chat does not get sent after pressing the 3 lines button or enter key, and you instead have to press the send button in the bottom right corner of the chat menu.

Expected Results: Whatever you've written in-chat should automatically get sent upon pressing the 3 lines button or enter key.