After the update that has happened around May 7, 2021, the output log is now buggy.

What I expected to happen:

Output log would look normal with white text and would cover the full window.

What actually happened:

Output log was in black (almost unreadable) text, and only covers about one third of the screen.

Reproduction:
Update to the latest version of Minecraft launcher

Start either 1.16.5 or 21w18a with output log on.