If I press the Scroll Lock button on the Terminal pane, it does not stop the text from scrolling as UART data is being received. Please fix in next release.
I believe what is happening is when the screen buffer if full, it pops out the oldest line, which moves the screen to make space for the new line coming in.
out of curiosity: I used Scroll-Lock (I have to admit I never used that):
Bottom line: it works for me as expected in 11.6.0 (I'm using Windows 10, if this matters): the target writes to the console/UART, and it is not scrolling. As expected.
I hope this helps,
Erich