Hey, this is a known issue with the chat input field. The text can jump upward when you type multiple lines, especially when the chat panel is docked on the side.
Here’s a detailed thread with the history of this bug: Agent Chat Text Input Cursor (Insertion Point) Desync Agent Chat Text Input Cursor (Insertion Point) Desync
As a workaround, if the text “disappears”, try scrolling inside the input field or starting a new chat.