Windows Terminal version (or Windows build number)

10.0.19043.1348, 1.12.2931.0

Other Software

Ubuntu 21.04 in WSL

Steps to reproduce

1. Open tab with some WSL distro, shouldn't matter which.

2. Create python3 file with the following content:

import os
import sys
cols = os.get_terminal_size().columns
sys.stdout.buffer.write(b'a'*(cols-1))
sys.stdout.buffer.write(b'\xea\xb0\x9c')

3. Run it:

python3 1.py

4. Copy output with the mouse and paste to some editor.

Expected Behavior

There should be only single line of text.

Actual Behavior

There're two lines of text, see screenshots.

The problem doesn't appear if that 3-byte symbol is not on the edge of the line. Also 2-byte symbols work fine too.