diff --git a/cpp/core/internal/bwu_manager.cc b/cpp/core/internal/bwu_manager.cc
index 4a21bd1c..b8b867ae 100644
--- a/cpp/core/internal/bwu_manager.cc
+++ b/cpp/core/internal/bwu_manager.cc
@@ -551,6 +551,7 @@ void BwuManager::RunUpgradeFailedProtocol(
   if (medium_ != Medium::UNKNOWN_MEDIUM) {
     Revert();
   }
+  in_progress_upgrades_.erase(endpoint_id);
 }
 
 bool BwuManager::ReadClientIntroductionFrame(EndpointChannel* channel,