diff --git a/thorlcr/graph/thgraphslave.cpp b/thorlcr/graph/thgraphslave.cpp
index 7e31640b07d..4b15f6ea4c8 100644
--- a/thorlcr/graph/thgraphslave.cpp
+++ b/thorlcr/graph/thgraphslave.cpp
@@ -589,7 +589,10 @@ unsigned __int64 CSlaveActivity::queryLocalCycles() const
     }
     unsigned __int64 processCycles = queryTotalCycles() + queryLookAheadCycles();
     if (processCycles < inputCycles) // not sure how/if possible, but guard against
+    {
+        ActPrintLog("CSlaveActivity::queryLocalCycles - process %" I64F "uns < inputCycles %" I64F "uns", cycle_to_nanosec(processCycles), cycle_to_nanosec(inputCycles));
         return 0;
+    }
     processCycles -= inputCycles;
     const unsigned __int64 blockedCycles = queryBlockedCycles();
     if (processCycles < blockedCycles)