S. Krezel - Smart Spline Generator

Hi, I’m trying to use this plugin / set of blueprints but I get a blueprint compile error right after I add the objects to a blank project.
"The following member variables in blueprint ‘Blueprint /Game/Blueprints/InternalLogic/StemSpline_BP.StemSpline_BP’ have invalid type. Would you like to remove them?

Sub Stem Starters
Meshes to Spawn Along
Skel Meshes to Spawn Along"

have tried in 4.19.2 and 4.20