fix:

(1) Fix that tooltip shows multiple values around both sides of the pointer. Fix #9829.
(2) Fix a probably typo (diff < maxDistance) introduced by https://github.com/apache/incubator-echarts/commit/4ef66e1d892485ced1dbfcf915135e7740bb7cc3
(3) Remove the previous logic to resolve #2869. Because currently if there are multiple values on the same axis tick, both of them will be found and displayed in tooltip by default. The related historical commits:
https://github.com/apache/incubator-echarts/commit/60d341f4ed9e33381099624962a8388eef8a9547  (fix #2869)
https://github.com/apache/incubator-echarts/commit/3426bd0e544b16f90a476cd36a79119c3570a63b  (support find multiple values on the same axis tick).

src/data/List.js

@@ -1159,23 +1159,31 @@ listProto.indicesOfNearest = function (dim, value, maxDistance) {
         maxDistance = Infinity;
     }
 
-    var minDist = Number.MAX_VALUE;
+    var minDist = Infinity;
     var minDiff = -1;
+    var nearestIndicesLen = 0;
     for (var i = 0, len = this.count(); i < len; i++) {
-        var diff = value - this.get(dim, i /*, stack */);
+        var diff = value - this.get(dim, i);
         var dist = Math.abs(diff);
-        if (diff <= maxDistance && dist <= minDist) {
-            // For the case of two data are same on xAxis, which has sequence data.
-            // Show the nearest index
-            // https://github.com/ecomfe/echarts/issues/2869
-            if (dist < minDist || (diff >= 0 && minDiff < 0)) {
+        if (dist <= maxDistance) {
+            // When the `value` is at the middle of `this.get(dim, i)` and `this.get(dim, i+1)`,
+            // we'd better not push both of them to `nearestIndices`, otherwise it is easy to
+            // get more than one item in `nearestIndices` (more specifically, in `tooltip`).
+            // So we chose the one that `diff >= 0` in this csae.
+            if (dist < minDist
+                || (dist === minDist && diff >= 0 && minDiff < 0)
+            ) {
                 minDist = dist;
                 minDiff = diff;
-                nearestIndices.length = 0;
+                nearestIndicesLen = 0;
+            }
+            if (diff === minDiff) {
+                nearestIndices[nearestIndicesLen++] = i;
             }
-            nearestIndices.push(i);
         }
     }
+    nearestIndices.length = nearestIndicesLen;
+
     return nearestIndices;
 };
 

test/runTest/actions/__meta__.json

@@ -128,6 +128,7 @@
   "toolbox-tooltip": 1,
   "tooltip": 10,
   "tooltip-axisPointer": 20,
+  "tooltip-axisPointer2": 1,
   "tooltip-cascade": 4,
   "tooltip-event": 1,
   "tooltip-link": 2,

test/runTest/actions/tooltip-axisPointer2.json

+[{"name":"Action 1","ops":[{"type":"mousemove","time":530,"x":31,"y":450},{"type":"mousemove","time":736,"x":57,"y":450},{"type":"mousemove","time":959,"x":82,"y":449},{"type":"mousemove","time":1163,"x":92,"y":447},{"type":"mousemove","time":1389,"x":93,"y":447},{"type":"mousemove","time":1634,"x":93,"y":447},{"type":"mousemove","time":1835,"x":114,"y":448},{"type":"mousemove","time":2051,"x":131,"y":448},{"type":"mousemove","time":2278,"x":142,"y":448},{"type":"mousemove","time":2522,"x":145,"y":447},{"type":"mousemove","time":3210,"x":148,"y":447},{"type":"mousemove","time":3428,"x":155,"y":445},{"type":"mousemove","time":3631,"x":156,"y":445},{"type":"mousemove","time":3834,"x":164,"y":445},{"type":"mousemove","time":4048,"x":183,"y":442},{"type":"mousemove","time":4251,"x":212,"y":439},{"type":"mousemove","time":4459,"x":221,"y":439},{"type":"mousemove","time":4662,"x":222,"y":439},{"type":"mousemove","time":4803,"x":224,"y":439},{"type":"mousemove","time":5005,"x":256,"y":435},{"type":"mousemove","time":5209,"x":281,"y":433},{"type":"mousemove","time":5411,"x":303,"y":433},{"type":"mousemove","time":5718,"x":307,"y":433},{"type":"mousemove","time":5933,"x":328,"y":431},{"type":"mousemove","time":6147,"x":352,"y":430},{"type":"mousemove","time":6373,"x":360,"y":430},{"type":"mousemove","time":6605,"x":361,"y":430},{"type":"mousemove","time":6949,"x":361,"y":430},{"type":"mousemove","time":7182,"x":374,"y":430},{"type":"mousemove","time":7404,"x":401,"y":430},{"type":"mousemove","time":7642,"x":402,"y":430},{"type":"mousemove","time":7821,"x":405,"y":430},{"type":"mousemove","time":8024,"x":418,"y":430},{"type":"mousemove","time":8251,"x":430,"y":430},{"type":"mousemove","time":8674,"x":434,"y":430},{"type":"mousemove","time":8903,"x":448,"y":431},{"type":"mousemove","time":9104,"x":498,"y":424},{"type":"mousemove","time":9330,"x":506,"y":424},{"type":"mousemove","time":9773,"x":511,"y":424},{"type":"mousemove","time":9995,"x":523,"y":426},{"type":"mousemove","time":10207,"x":543,"y":424},{"type":"mousemove","time":10415,"x":570,"y":422},{"type":"mousemove","time":10649,"x":577,"y":422},{"type":"mousemove","time":10921,"x":581,"y":422},{"type":"mousemove","time":11149,"x":645,"y":419},{"type":"mousemove","time":11375,"x":646,"y":418}],"scrollY":0,"scrollX":0,"timestamp":1573747705006}]
\ No newline at end of file