rep:policy node is missing under a group



I had a group which was working perfectly, suddenly one day I start facing the issue when I try to modify anything in the AEM. Everything I found correct even all permission given to that group is already there. After a long struggle and research, I found that node rep:policy under the group is missing from CRX, I didn’t understand why and how this happened, how this node gets vanished automatically from crx. Any idea why this get deleted automatically? Or any scenarios due to that node rep:policy automatically remove?