The Caverns II mod portals form but no longer function with BetterPortals installed. The portal animation will display but when stepping through, no longer teleports the player to the Cavern dimension. Once BetterPortals is removed from the pack, the Cavern II portals begin to function as normal.

After testing the latest release of this mod, it appears the bug still exists.

Last release was seven days ago. The above fix hasn't yet made it to curseforge (though it probably will today).