The WordPress object-cache.php file is used by several different caching plugins for DB Object caching. So I guess SiteGround SuperCacher also uses the WordPress object-cache.php file. To create an AutoRestore Single File Exclude rule so that ARQ will not check this file do these steps:
1. Go to AutoRestore and turn Off AutoRestore.
2. Go to Quarantine and restore the object-cache.php file from Quarantine.
3. Go to AutoRestore > Add|Exclude Other Folders & Files tab > under Exclude Folders & Files > select Exclude An Individual File > Enter an Exclude Folder or File Path in the text box (you can get that path from your Quarantine Log) and click the Exclude button.
4. Turn AutoRestore back On.
Other Help Info: AutoRestore|Quarantine Exclude Folders & Files Video Tutorial: http://forum.ait-pro.com/video-tutorials/#autorestore-quarantine