fix: prevent race condition

server_cached_router.go

@@ -154,10 +154,10 @@ func (it *cacheFallbackIter) Next() bool {
 				return true
 			}
 			logger.Infow("no cached addresses found in cacheFallbackIter, dispatching find peers", "peer", id)
+
+			it.ongoingLookups.Add(1) // important to increment here since Next() may be called again synchronously
 			// If a record has no addrs, we dispatch a lookup to find addresses
 			go it.dispatchFindPeer(*record)
-			// important to increment here since Next() may be called again synchronously
-			it.ongoingLookups.Add(1)
 
 			return it.Next() // Recursively call Next() to either read from sourceIter or wait for lookup result
 		}