Previous selection was returning the entire node and edge objects rather than just an array of ids. This fixes it. I only tested it via modifying the vis-network.min.js file directly, but have translated it back to this format. Please check and improve as necessary. 
`
  value: function (g, A) {
                    var t = !1,
                        e = this._selectionAccumulator.commit(),
                        C = {},
                        nodes = [], 
                        edges = [];
                    
                    for (let i = 0; i < e.nodes.previous.length; i++ ){
                        nodes.push(e.nodes.previous[i].id);
                    };
                    for (let i = 0; i < e.edges.previous.length; i++ ){
                        edges.push(e.edges.previous[i].id);
                    };
                    
                    C = {
                        nodes: nodes,
                        edges: edges
                    };
`