diff --git a/src/nupic/algorithms/SpatialPooler.cpp b/src/nupic/algorithms/SpatialPooler.cpp
index bd8b366173..3617aeb08e 100644
--- a/src/nupic/algorithms/SpatialPooler.cpp
+++ b/src/nupic/algorithms/SpatialPooler.cpp
@@ -186,7 +186,7 @@ UInt SpatialPooler::getPotentialRadius() const
 
 void SpatialPooler::setPotentialRadius(UInt potentialRadius)
 {
-  potentialRadius_ = potentialRadius;
+  potentialRadius_ = std::min(potentialRadius, numInputs_); //crop to numInputs (input size)
 }
 
 Real SpatialPooler::getPotentialPct() const
@@ -196,6 +196,7 @@ Real SpatialPooler::getPotentialPct() const
 
 void SpatialPooler::setPotentialPct(Real potentialPct)
 {
+  NTA_ASSERT(potentialPct > 0 && potentialPct <= 1); //bounds check
   potentialPct_ = potentialPct;
 }
 
@@ -219,7 +220,7 @@ void SpatialPooler::setNumActiveColumnsPerInhArea(
 {
   NTA_ASSERT(numActiveColumnsPerInhArea > 0);
   numActiveColumnsPerInhArea_ = numActiveColumnsPerInhArea;
-  localAreaDensity_ = 0;
+  localAreaDensity_ = -1; //disabling
 }
 
 Real SpatialPooler::getLocalAreaDensity() const
@@ -231,7 +232,7 @@ void SpatialPooler::setLocalAreaDensity(Real localAreaDensity)
 {
   NTA_ASSERT(localAreaDensity > 0 && localAreaDensity <= 1);
   localAreaDensity_ = localAreaDensity;
-  numActiveColumnsPerInhArea_ = 0;
+  numActiveColumnsPerInhArea_ = 0; //disabling
 }
 
 UInt SpatialPooler::getStimulusThreshold() const
diff --git a/src/test/unit/algorithms/SpatialPoolerTest.cpp b/src/test/unit/algorithms/SpatialPoolerTest.cpp
index 88f3882a2e..17b2d3090f 100644
--- a/src/test/unit/algorithms/SpatialPoolerTest.cpp
+++ b/src/test/unit/algorithms/SpatialPoolerTest.cpp
@@ -2222,6 +2222,46 @@ namespace {
     EXPECT_EQ(0, countNonzero(activeColumns));
   }
 
+
+  TEST(SpatialPoolerTest, testDifferentConstructorVsSetterBehavior)
+  {
+  /** this test exposes wrong behavior, where SP created via constructor
+  behaves differently to a SP via setters (setXXX()), both with the same
+  params. 
+  */
+    SpatialPooler spConstruct{std::vector<UInt>{10} /* input*/, std::vector<UInt>{2048}/* SP output cols XXX sensitive*/,
+                        /*pot radius*/ 20, //each col sees
+                        /*pot pct*/ 0.5, //XXX sensitive
+                        /*global inhibition*/ false, //XXX sensitive
+                       /*Real localAreaDensity=*/0.02, //2% active cols
+                       /*UInt numActiveColumnsPerInhArea=*/0, //mutex with above ^^ //XXX sensitive
+};
+
+    SpatialPooler  sp{std::vector<UInt>{10} /* input*/, std::vector<UInt>{2048}/* SP output cols */};
+sp.setPotentialRadius(20);
+sp.setPotentialPct(0.5);
+sp.setGlobalInhibition(false);
+sp.setLocalAreaDensity(0.02); //2% active cols
+//! sp.setNumActiveColumnsPerInhArea(0); //mutex with above ^^
+
+  // test 1: these two mutex settings had err compared to the API 
+  // (localAreaDensity & numActiveColumnsPerInhArea)
+  sp.setNumActiveColumnsPerInhArea(5);
+  EXPECT_EQ(sp.getNumActiveColumnsPerInhArea(), 5);
+  EXPECT_FLOAT_EQ(sp.getLocalAreaDensity(), -1); //-1 means disabled
+
+  sp.setLocalAreaDensity(0.02);
+  EXPECT_EQ(sp.getNumActiveColumnsPerInhArea(), 0); //0 means disabled
+  EXPECT_FLOAT_EQ(sp.getLocalAreaDensity(), 0.02);
+
+  //test 2: compare potentialRadius
+  EXPECT_EQ(sp.getPotentialRadius(), spConstruct.getPotentialRadius());
+
+  //    EXPECT_EQ(spConstruct, sp);  //FIXME how compare 2 SP
+  check_spatial_eq(spConstruct, sp);
+}
+
+
   TEST(SpatialPoolerTest, testSaveLoad)
   {
     const char* filename = "SpatialPoolerSerialization.tmp";