diff --git a/pcbnew/drc/drc_test_provider_diff_pair_coupling.cpp b/pcbnew/drc/drc_test_provider_diff_pair_coupling.cpp
index 40a27a23f9..c7a21e00b7 100644
--- a/pcbnew/drc/drc_test_provider_diff_pair_coupling.cpp
+++ b/pcbnew/drc/drc_test_provider_diff_pair_coupling.cpp
@@ -209,7 +209,9 @@ static void extractDiffPairCoupledItems( DIFF_PAIR_ITEMS& aDp, DRC_RTREE& aTree
             SEG ssp ( sp->GetStart(), sp->GetEnd() );
             SEG ssn ( sn->GetStart(), sn->GetEnd() );
 
-            if( ssp.ApproxParallel(ssn) )
+            // Segments that are == 1 IU in length are approximately parallel with everything and their
+            // parallel projection is < 1 IU, leading to bad distance calculations
+            if( ssp.SquaredLength() > 1 && ssn.SquaredLength() > 1 && ssp.ApproxParallel(ssn) )
             {
                 DIFF_PAIR_COUPLED_SEGMENTS cpair;
                 bool coupled = commonParallelProjection( ssp, ssn, cpair.coupledP, cpair.coupledN );