Refresh Rate Locked to Primary Monitor (Borderless Mode)

It appears that borderless mode can not be used properly if the player is gaming on their secondary monitor. When gaming on the secondary monitor, if the player switches to borderless mode (preferred), the refresh rate option is greyed out and locked to the refresh rate of the primary monitor, which in my case is 60hz. So I can't play on my 120hz, secondary monitor in borderless mode.

The only workaround is for me to switch to fullscreen mode, which is not ideal.

This was not an issue in the open beta. This problem was introduced in the full release of the game.

I attached a couple of images showing the problem.

So, what happened? What was changed from the open beta, to full release for this to happen?