diff --git a/python/core/auto_generated/qgsmapsettings.sip.in b/python/core/auto_generated/qgsmapsettings.sip.in
index e9600336223f..781ff949d5ee 100644
--- a/python/core/auto_generated/qgsmapsettings.sip.in
+++ b/python/core/auto_generated/qgsmapsettings.sip.in
@@ -526,7 +526,7 @@ transform point coordinates from layer's CRS to output CRS
 :return: the transformed point
 %End
 
-    QgsPoint layerToMapCoordinates( const QgsMapLayer *layer, QgsPoint point ) const;
+    QgsPoint layerToMapCoordinates( const QgsMapLayer *layer, const QgsPoint &point ) const;
 %Docstring
 transform point coordinates from layer's CRS to output CRS
 
@@ -551,7 +551,7 @@ transform point coordinates from output CRS to layer's CRS
 :return: the transformed point
 %End
 
-    QgsPoint mapToLayerCoordinates( const QgsMapLayer *layer, QgsPoint point ) const;
+    QgsPoint mapToLayerCoordinates( const QgsMapLayer *layer, const QgsPoint &point ) const;
 %Docstring
 transform point coordinates from output CRS to layer's CRS
 
diff --git a/src/core/qgsmapsettings.cpp b/src/core/qgsmapsettings.cpp
index 0c2ba10cd5cd..4f492ec5971c 100644
--- a/src/core/qgsmapsettings.cpp
+++ b/src/core/qgsmapsettings.cpp
@@ -496,11 +496,11 @@ QgsPointXY QgsMapSettings::layerToMapCoordinates( const QgsMapLayer *layer, QgsP
   return point;
 }
 
-QgsPoint QgsMapSettings::layerToMapCoordinates( const QgsMapLayer *layer, QgsPoint point ) const
+QgsPoint QgsMapSettings::layerToMapCoordinates( const QgsMapLayer *layer, const QgsPoint &point ) const
 {
   double x = point.x();
   double y = point.y();
-  double z = point.z();
+  double z = !std::isnan( point.z() ) ? point.z() : 0.0;
 
   try
   {
@@ -513,7 +513,7 @@ QgsPoint QgsMapSettings::layerToMapCoordinates( const QgsMapLayer *layer, QgsPoi
     QgsMessageLog::logMessage( QObject::tr( "Transform error caught: %1" ).arg( cse.what() ), QObject::tr( "CRS" ) );
   }
 
-  return QgsPoint( x, y, z );
+  return QgsPoint( x, y, !std::isnan( point.z() ) ? z : point.z() );
 }
 
 
@@ -550,11 +550,11 @@ QgsPointXY QgsMapSettings::mapToLayerCoordinates( const QgsMapLayer *layer, QgsP
   return point;
 }
 
-QgsPoint QgsMapSettings::mapToLayerCoordinates( const QgsMapLayer *layer, QgsPoint point ) const
+QgsPoint QgsMapSettings::mapToLayerCoordinates( const QgsMapLayer *layer, const QgsPoint &point ) const
 {
   double x = point.x();
   double y = point.y();
-  double z = point.z();
+  double z = !std::isnan( point.z() ) ? point.z() : 0.0;
 
   try
   {
@@ -567,7 +567,7 @@ QgsPoint QgsMapSettings::mapToLayerCoordinates( const QgsMapLayer *layer, QgsPoi
     QgsMessageLog::logMessage( QObject::tr( "Transform error caught: %1" ).arg( cse.what() ), QObject::tr( "CRS" ) );
   }
 
-  return QgsPoint( x, y, z );
+  return QgsPoint( x, y, !std::isnan( point.z() ) ? z : point.z() );
 }
 
 
diff --git a/src/core/qgsmapsettings.h b/src/core/qgsmapsettings.h
index dd4e5e6550ff..8a4c6ebfa084 100644
--- a/src/core/qgsmapsettings.h
+++ b/src/core/qgsmapsettings.h
@@ -468,7 +468,7 @@ class CORE_EXPORT QgsMapSettings : public QgsTemporalRangeObject
      * \returns the transformed point
      * \since QGIS 3.16
      */
-    QgsPoint layerToMapCoordinates( const QgsMapLayer *layer, QgsPoint point ) const;
+    QgsPoint layerToMapCoordinates( const QgsMapLayer *layer, const QgsPoint &point ) const;
 
     /**
      * \brief transform rectangle from layer's CRS to output CRS
@@ -488,7 +488,7 @@ class CORE_EXPORT QgsMapSettings : public QgsTemporalRangeObject
      * \returns the transformed point
      * \since QGIS 3.16
      */
-    QgsPoint mapToLayerCoordinates( const QgsMapLayer *layer, QgsPoint point ) const;
+    QgsPoint mapToLayerCoordinates( const QgsMapLayer *layer, const QgsPoint &point ) const;
 
     /**
      * \brief transform rectangle from output CRS to layer's CRS