Borderless Windowed JVM Argument issue not resolved

ATTENTION: I HAVE SEEN THE PREVIOUS THREAD ON THIS ISSUE BUT THE GIVEN "SOLUTION" DOES NOT PROVIDE A FIX FOR THIS ISSUE.

The following JVM argument does not apply when used in launcher profiles:

-Dorg.lwjgl.opengl.Window.undecorated=true

This should start the game in a borderless window, however using this currently does nothing. This was working the other day but after I wiped my PC and reinstalled everything, it no longer works.

Again, the previous given "solution" does not apply because in the logs, no spaces are injected between the equal signs.