diff --git a/src/net_processing.cpp b/src/net_processing.cpp
--- a/src/net_processing.cpp
+++ b/src/net_processing.cpp
@@ -170,8 +170,8 @@
 int nSyncStarted GUARDED_BY(cs_main) = 0;
 
 /**
- * Sources of received blocks, saved to be able to send them reject messages or
- * ban them when processing happens afterwards.
+ * Sources of received blocks, saved to be able to punish them when processing
+ * happens afterwards.
  * Set mapBlockSource[hash].second to false if the node should not be punished
  * if the block is invalid.
  */
@@ -3396,16 +3396,17 @@
                 // been run). This is handled below, so just treat this as
                 // though the block was successfully read, and rely on the
                 // handling in ProcessNewBlock to ensure the block index is
-                // updated, reject messages go out, etc.
+                // updated, etc.
 
                 // it is now an empty pointer
                 MarkBlockAsReceived(resp.blockhash);
                 fBlockRead = true;
-                // mapBlockSource is only used for sending reject messages and
-                // DoS scores, so the race between here and cs_main in
-                // ProcessNewBlock is fine. BIP 152 permits peers to relay
-                // compact blocks after validating the header only; we should
-                // not punish peers if the block turns out to be invalid.
+                // mapBlockSource is used for potentially punishing peers and
+                // updating which peers send us compact blocks, so the race
+                // between here and cs_main in ProcessNewBlock is fine.
+                // BIP 152 permits peers to relay compact blocks after
+                // validating the header only; we should not punish peers
+                // if the block turns out to be invalid.
                 mapBlockSource.emplace(resp.blockhash,
                                        std::make_pair(pfrom->GetId(), false));
             }
@@ -3488,9 +3489,9 @@
             // Also always process if we requested the block explicitly, as we
             // may need it even though it is not a candidate for a new best tip.
             forceProcessing |= MarkBlockAsReceived(hash);
-            // mapBlockSource is only used for sending reject messages and DoS
-            // scores, so the race between here and cs_main in ProcessNewBlock
-            // is fine.
+            // mapBlockSource is only used for punishing peers and setting
+            // which peers send us compact blocks, so the race between here and
+            // cs_main in ProcessNewBlock is fine.
             mapBlockSource.emplace(hash, std::make_pair(pfrom->GetId(), true));
         }
         bool fNewBlock = false;