4.7 procedural spline migration issues

I’ve migrated a fairly extensive procedural spline from 4.6 to 4.7. In 4.6, when i selected the spline in-editor, i could immediately continue to work on it and either add points, delete points, move, etc. however, in 4.7, whenever i select the spline in editor, ue4 freezes for about 5 min. any idea what might be causing this, or how to resolve this?