consider case where kpj is NaN for K value calculation on graph

yafitsv/views/olqv.ejs

@@ -1710,7 +1710,11 @@
                 },
                 tooltip: {
                       formatter: function () {
-                        return '( ' + this.x.toFixed(4) + ', ' + this.y.toFixed(4) + '), ' + Number(this.y * kpj ).toExponential(2) + " K";
+                        let label = '( ' + this.x.toFixed(4) + ', ' + this.y.toFixed(4) + ') ';
+                        if(!isNaN(kpj)){
+                          label = label + ", " + Number(this.y * kpj ).toExponential(2) + " K";
+                        }
+                        return label;
                       }
                 },
                 series: [