Since commit ddbe370 (#6506) a black background appears after space in commands while using PowerShell.

Environment

Windows build number: 10.0.19041.329
Windows Terminal versions: all since commit ddbe370

Steps to reproduce

1. Open PowerShell (tested in 5.1 and 7.0.2)
2. Do either of these:
   • press space,
   • write anything and press space,
   • use the arrow up to display a command from history that contains a space character.

Expected behavior

The background colour does not change and the acrylic effect is visible.

Actual behavior

A weird black background appears after the space character.