adjusted comments + bug fix

src/elements/Entry.php

@@ -1239,6 +1239,10 @@ public function setAuthorsIds(array|string|int|null $authorsIds): void
             $authorsIds = null;
         }
 
+        if (is_string($authorsIds)) {
+            $authorsIds = explode(',', $authorsIds);
+        }
+
         if (is_int($authorsIds)) {
             $this->_authorsIds = [$authorsIds];
         }
@@ -1248,6 +1252,9 @@ public function setAuthorsIds(array|string|int|null $authorsIds): void
                 if ($authorId == '') {
                     return null;
                 }
+                if (is_string($authorId)) {
+                    return (int)$authorId;
+                }
                 if ($authorId instanceof User) {
                     return $authorId->id;
                 }

src/elements/db/EntryQuery.php

@@ -1139,8 +1139,9 @@ protected function cacheTags(): array
      */
     private function _processAuthors(array $rows): array
     {
-        // we are now getting multiple rows for one entry because of ->authorId([...]), ->authorsIds([...])
-        // and the ->innerJoin with entries_authors table
+        // get authors info
+        // also, because of ->authorId([...]), ->authorsIds([...]) we are now
+        // getting multiple rows for one entry
         // todo: is there a better way to do this? tried with group_concat but throws mysql error
         $distinctRows = [];
         if (!empty($rows)) {
@@ -1161,7 +1162,7 @@ private function _processAuthors(array $rows): array
 
                 // if authors IDs were passed via authorsIds
                 // make sure we only return entries which have all and only
-                // the specified authors assigned to them
+                // the specified authors from the query
                 if (!empty($this->authorsIds)) {
                     if (strtolower(trim($this->authorsIds[0])) === 'not') {
                         $negativeSearch = true;