Fails to launch in Modrinth App

[CodeF53]

Type of Instance

Single Player

Installation Target

Your Own Computer or Laptop

Your Actions

Attempting to install the modpack in Modrinth App (modrinth's own launcher)

1. install Modrinth app https://modrinth.com/app
2. go through launcher onboarding (log in with microsoft account...)
3. search for and install pack
4. click play on the new instance.

Your Pack Version

1.6.1

Required Logs

No logs folder exists inside the instance's folder.

Exception in thread "main" java.lang.ClassCastException: class jdk.internal.loader.ClassLoaders$AppClassLoader cannot be cast to class java.net.URLClassLoader (jdk.internal.loader.ClassLoaders$AppClassLoader and java.net.URLClassLoader are in module java.base of loader 'bootstrap')
    at net.minecraft.launchwrapper.Launch.<init>(Launch.java:34)
    at net.minecraft.launchwrapper.Launch.main(Launch.java:28)

Final Checklist

• [X] I have provided all the required logs.
• [X] I searched this issue tracker and there is nothing similar already.
• [X] I can reproduce this crash consistently by following the exact steps I described above.

[DrParadox7]

Trying to run a modpack needing Java 8 on Java 9+.