When using a physical keyboard (and mouse), about 9 out of 10 times, pressing the 'Enter' key in chat when you're done typing doesn't send the message / command that you typed. This forces you to manually press the 'Send' button in the bottom right every time you're done typing. This issue started happening since Keyboard & Mouse support was introduced in 1.19.10.

Observed results:
When pressing the enter key, the text input field is simply deselected instead of the message being sent like it does on other platforms

Expected results:
When the enter key is pressed, the entered text should be sent instead of the field being deselected

In the video I attached, you can see the textbox was simply deselected when I pressed the 'Enter' key on my keyboard, except for the last time when the command was sent successfully.

The same issue is also present on Xbox, see my report MCPE-170890