Don't set a source model on the attribute when it's not needed. This avoids accidentally persisting the source model to the database when using multiselect attributes.

hostep · hostep · commit 477ca51d0524 · 2018-09-25T19:57:09.000+02:00
diff --git a/app/code/Magento/Eav/Model/Entity/Attribute/AbstractAttribute.php b/app/code/Magento/Eav/Model/Entity/Attribute/AbstractAttribute.php
@@ -608,9 +608,11 @@ public function getSource()
     {
         if (empty($this->_source)) {
             if (!$this->getSourceModel()) {
-                $this->setSourceModel($this->_getDefaultSourceModel());
+                $this->_source = $this->_getDefaultSourceModel();
+            } else {
+                $this->_source = $this->getSourceModel();
             }
-            $source = $this->_universalFactory->create($this->getSourceModel());
+            $source = $this->_universalFactory->create($this->_source);
             if (!$source) {
                 throw new LocalizedException(
                     __(

Original file line number	Diff line number	Diff line change
`@@ -608,9 +608,11 @@ public function getSource()`
`608`	`608`	`{`
`609`	`609`	`if (empty($this->_source)) {`
`610`	`610`	`if (!$this->getSourceModel()) {`
`611`		`- $this->setSourceModel($this->_getDefaultSourceModel());`
	`611`	`+ $this->_source = $this->_getDefaultSourceModel();`
	`612`	`+ } else {`
	`613`	`+ $this->_source = $this->getSourceModel();`
`612`	`614`	`}`
`613`		`- $source = $this->_universalFactory->create($this->getSourceModel());`
	`615`	`+ $source = $this->_universalFactory->create($this->_source);`
`614`	`616`	`if (!$source) {`
`615`	`617`	`throw new LocalizedException(`
`616`	`618`	`__(`