New Launcher doesn't respect changes to APPDATA location

We're in an environment that uses network home dirs. In the past, we've convinced the Minecraft launcher to store things in the users' homes by calling "set APPDATA=H:\Documents\Minecraft\" in a shell script before launch. New launcher doesn't respect this setting, and just uses the default APPDATA location on C:. This is bad.

What I expected to happen was...:
Launcher would respect manual changes to the current APPDATA location.

What actually happened was...:
Launcher ignores this change.

Steps to Reproduce:
1. Call "set APPDATA=H:\Documents\Minecraft\"
2. Launch Minecraft.
3. Notice that all data files are being stored in the old APPDATA location on C:.