add comment about set after no-longer-master

server/src/main/java/org/elasticsearch/cluster/routing/allocation/allocator/DesiredBalanceShardsAllocator.java

@@ -131,6 +131,10 @@ protected void processInput(DesiredBalanceInput desiredBalanceInput) {
 
                 recordTime(
                     cumulativeComputationTime,
+                    // We set currentDesiredBalance back to INITIAL when the node stands down as master in onNoLongerMaster.
+                    // However, it is possible that we revert the effect here by setting it again since the computation is async
+                    // and does not check whether the node is master. This should have little to no practical impact. But it may
+                    // lead to unexpected behaviours for tests. See also https://github.com/elastic/elasticsearch/pull/116904
                     () -> setCurrentDesiredBalance(
                         desiredBalanceComputer.compute(
                             getInitialDesiredBalance(),
@@ -214,7 +218,7 @@ public void allocate(RoutingAllocation allocation, ActionListener<Void> listener
         desiredBalanceComputation.onNewInput(DesiredBalanceInput.create(index, allocation));
 
         if (allocation.routingTable().indicesRouting().isEmpty()) {
-            logger.debug("No reconciliation needed for empty routing table");
+            logger.debug("No eager reconciliation needed for empty routing table");
             return;
         }
         // Starts reconciliation towards desired balance that might have not been updated with a recent calculation yet.