I installed 3 modpacks yesterday, and already had 3 installed from over a year ago.
The old ones function perfectly, and load up forge with the mods in the according forge version.
But all new modpacks only launch the vanilla version, and not forge. This also does obviously not load the mods.
I am using the newest version of the overwolf curseforge launcher. This may happen because it shows "N/A" in the modloader field in the modpack options.