diff --git a/ext/simplexml/simplexml.c b/ext/simplexml/simplexml.c
index 0e02a843e95a..e81a2193a623 100644
--- a/ext/simplexml/simplexml.c
+++ b/ext/simplexml/simplexml.c
@@ -1107,7 +1107,14 @@ static HashTable *sxe_get_prop_hash(zend_object *object, int is_debug) /* {{{ */
 	}
 
 	GET_NODE(sxe, node);
-	node = php_sxe_get_first_node_non_destructive(sxe, node);
+	if (sxe->iter.type == SXE_ITER_CHILD) {
+		/* Start at the first child rather than at the first element child, so that
+		 * non-element nodes (e.g. PIs, comments) before it are not skipped. Like
+		 * sxe_prop_is_empty(), only do so if there is a matching element child. */
+		node = php_sxe_get_first_node_non_destructive(sxe, node) ? node->children : NULL;
+	} else {
+		node = php_sxe_get_first_node_non_destructive(sxe, node);
+	}
 
 	if (node && sxe->iter.type != SXE_ITER_ATTRLIST) {
 		if (node->type == XML_ATTRIBUTE_NODE) {
@@ -1128,7 +1135,7 @@ static HashTable *sxe_get_prop_hash(zend_object *object, int is_debug) /* {{{ */
 		}
 
 		while (node) {
-			if (node->children != NULL || node->prev != NULL || node->next != NULL || xmlIsBlankNode(node)) {
+			if (node->children != NULL || node->prev != NULL || node->next != NULL || xmlIsBlankNode(node) || sxe->iter.type == SXE_ITER_CHILD) {
 				SKIP_TEXT(node);
 			} else {
 				if (node->type == XML_TEXT_NODE) {
diff --git a/ext/simplexml/tests/gh12168.phpt b/ext/simplexml/tests/gh12168.phpt
new file mode 100644
index 000000000000..3f4cd9bba986
--- /dev/null
+++ b/ext/simplexml/tests/gh12168.phpt
@@ -0,0 +1,74 @@
+--TEST--
+GH-12168 (Mixing processing instructions and element nodes gives inconsistent results in SimpleXML)
+--EXTENSIONS--
+simplexml
+--FILE--
+<?php
+
+$sxe = simplexml_load_string('<container><x/><?hello world?></container>');
+var_dump($sxe->children());
+
+$sxe = simplexml_load_string('<container><?hello world?><x/></container>');
+var_dump($sxe->children());
+
+foreach ([
+    '<c><!-- c --><x/></c>',
+    '<c><x/><!-- c --></c>',
+    '<c><?pi a?><x/><?pi b?><y/></c>',
+    '<c>text</c>',
+] as $xml) {
+    $sxe = simplexml_load_string($xml);
+    echo $xml, ': ', json_encode(array_keys((array) $sxe->children())), "\n";
+}
+
+/* Non-element nodes only show up alongside a matching element, consistent with (bool) */
+foreach ([
+    '<c><?pi a?></c>',
+    '<c><!-- c --></c>',
+    '<c>t<?pi a?></c>',
+    '<!DOCTYPE c [<!ENTITY e "v">]><c>&e;<x/></c>',
+] as $xml) {
+    $sxe = simplexml_load_string($xml);
+    echo $xml, ': ', json_encode(array_keys((array) $sxe->children())), ' ', var_export((bool) $sxe->children(), true), "\n";
+}
+
+$sxe = simplexml_load_string('<c xmlns:a="urn:a"><?pi a?><y/><a:x/></c>');
+var_dump(array_keys((array) $sxe->children('urn:a')));
+$sxe = simplexml_load_string('<c xmlns:a="urn:a"><?pi a?><y/></c>');
+var_dump(array_keys((array) $sxe->children('urn:a')), (bool) $sxe->children('urn:a'));
+
+?>
+--EXPECTF--
+object(SimpleXMLElement)#%d (2) {
+  ["x"]=>
+  object(SimpleXMLElement)#%d (0) {
+  }
+  ["hello"]=>
+  object(SimpleXMLElement)#%d (0) {
+  }
+}
+object(SimpleXMLElement)#%d (2) {
+  ["hello"]=>
+  object(SimpleXMLElement)#%d (0) {
+  }
+  ["x"]=>
+  object(SimpleXMLElement)#%d (0) {
+  }
+}
+<c><!-- c --><x/></c>: ["comment","x"]
+<c><x/><!-- c --></c>: ["x","comment"]
+<c><?pi a?><x/><?pi b?><y/></c>: ["pi","x","y"]
+<c>text</c>: []
+<c><?pi a?></c>: [] false
+<c><!-- c --></c>: [] false
+<c>t<?pi a?></c>: [] false
+<!DOCTYPE c [<!ENTITY e "v">]><c>&e;<x/></c>: ["e","x"] true
+array(2) {
+  [0]=>
+  string(2) "pi"
+  [1]=>
+  string(1) "x"
+}
+array(0) {
+}
+bool(false)