I have confirmed for whatever reason, the changes made to CheckPlaced is the culprit. As soon as I replaced .16's version of CheckPlaced with .14's version of CheckPlaced, everything started to work.

Meaning, download the latest version of CopyPaste, then open CopyPaste.cs and replace

This should at least do us in while we give misticos time to rewrite this plugin.

        private bool CheckPlaced(string prefabname, Vector3 pos, Quaternion rot)
        {
            const float maxDiff = 0.05f;
            
            var ents = new List();
            Vis.Entities(pos, maxDiff, ents);

            foreach (var ent in ents)
            {
                if (ent.PrefabName != prefabname)
                    continue;
                
                if (Vector3.Distance(ent.transform.rotation.eulerAngles, rot.eulerAngles) > maxDiff)
                {
                    continue;
                }

                return true;
            }​

With

        private bool CheckPlaced(string prefabname, Vector3 pos, Quaternion rot)
        {
            List ents = new List();
            Vis.Entities(pos, 2f, ents);
            foreach (BaseEntity ent in ents)
            {
                if (ent.PrefabName == prefabname && ent.transform.position == pos && ent.transform.rotation == rot) 
                    return true;
            }
            return false;
        }

Then save CopyPaste.cs and then in console run   o.reload CopyPaste  and then   plugins   to confirm it loaded fine.

Thanks Asweiler. Would tip you some BAT if uMod supported it.