diff --git a/CHANGELOG-v3.md b/CHANGELOG-v3.md
index a05abdb12ec..368900008e7 100644
--- a/CHANGELOG-v3.md
+++ b/CHANGELOG-v3.md
@@ -8,6 +8,7 @@
 ### Changed
 - Craft no longer shows the status menu for element sources that define a status. ([#4249](https://github.com/craftcms/cms/issues/4249))
 - Element URI formats can now conditionally output an empty string, opting the element out of getting its own system URI. ([#4254](https://github.com/craftcms/cms/issues/4254))
+- Table fields now get validation errors if any column handles are entered in the format of “colX”.
 
 ### Fixed
 - Fixed a bug where rebuilding the project config could set an incorrect value for the user field layout.
@@ -18,6 +19,7 @@
 - Fixed a bug that could occur when Craft generated URLs with multi-byte characters in the query string.
 - Fixed a bug where you could get some character encoding issues in some environments when using PHP 7.3.
 - Fixed a bug where Craft wasn’t attempting to set a unique URI on duplicated elements. ([#4253](https://github.com/craftcms/cms/issues/4253))
+- Fixed a bug where Table fields could copy cell values to other cells if a column had a handle in the format of “colX”. ([#4200](https://github.com/craftcms/cms/issues/4200))
 
 ## 3.1.26 - 2019-05-08
 
diff --git a/src/fields/Table.php b/src/fields/Table.php
index cf8e416a7f2..059104bdc70 100644
--- a/src/fields/Table.php
+++ b/src/fields/Table.php
@@ -125,9 +125,32 @@ public function rules()
         $rules[] = [['minRows'], 'compare', 'compareAttribute' => 'maxRows', 'operator' => '<=', 'type' => 'number', 'when' => [$this, 'hasMaxRows']];
         $rules[] = [['maxRows'], 'compare', 'compareAttribute' => 'minRows', 'operator' => '>=', 'type' => 'number', 'when' => [$this, 'hasMinRows']];
         $rules[] = [['minRows', 'maxRows'], 'integer', 'min' => 0];
+        $rules[] = [['columns'], 'validateColumns'];
         return $rules;
     }
 
+    /**
+     * Validatse the column configs.
+     */
+    public function validateColumns()
+    {
+        $hasErrors = false;
+        foreach ($this->columns as &$col) {
+            if ($col['handle'] && preg_match('/^col\d+$/', $col['handle'])) {
+                $col['handle'] = [
+                    'value' => $col['handle'],
+                    'hasErrors' => true,
+                ];
+                $hasErrors = true;
+            }
+        }
+        if ($hasErrors) {
+            $this->addError('columns', Craft::t('app', 'Column handles can’t be in the format “{format}”.', [
+                'format' => 'colX',
+            ]));
+        }
+    }
+
     /**
      * @return bool whether minRows was set
      */
@@ -217,7 +240,8 @@ public function getSettingsHtml()
                 'cols' => $columnSettings,
                 'rows' => $this->columns,
                 'addRowLabel' => Craft::t('app', 'Add a column'),
-                'initJs' => false
+                'initJs' => false,
+                'errors' => $this->getErrors('columns'),
             ]
         ]);
 
@@ -297,7 +321,7 @@ public function normalizeValue($value, ElementInterface $element = null)
         foreach ($value as &$row) {
             foreach ($this->columns as $colId => $col) {
                 $row[$colId] = $this->_normalizeCellValue($col['type'], $row[$colId] ?? null);
-                if ($col['handle']) {
+                if ($col['handle'] && !isset($this->columns[$col['handle']])) {
                     $row[$col['handle']] = $row[$colId];
                 }
             }