Don't cache CNContact.

Signal/src/ViewControllers/DebugUI/DebugUIMisc.m

@@ -133,6 +133,11 @@ NS_ASSUME_NONNULL_BEGIN
                             }
                         }]];
 
+    [items addObject:[OWSTableItem itemWithTitle:@"Fetch system contacts"
+                                     actionBlock:^() {
+                                         [Environment.current.contactsManager requestSystemContactsOnce];
+                                     }]];
+
     return [OWSTableSection sectionWithTitle:self.name items:items];
 }