diff --git a/lib_com/ivas_prot.h b/lib_com/ivas_prot.h
index 5ef73792aa5da25651fc53a9c256c82bd5c7bf97..a84cf477f81463086eaca16592407ece81580ceb 100644
--- a/lib_com/ivas_prot.h
+++ b/lib_com/ivas_prot.h
@@ -5142,6 +5142,10 @@ void ivas_masa_prerender(
     Decoder_Struct *st_ivas,                                    /* i/o: IVAS decoder handle                             */
     float output[][L_FRAME48k],                                 /* i/o: synthesized core-coder transport channels       */
     const int16_t output_frame                                  /* i  : output frame length per channel                 */
+#ifdef CR_FIX_585_MASA_2TC_DTX_EXT
+    ,
+    const int16_t nchan_remapped                                /* i  : number of transports used in core               */
+#endif
 );
 
 
diff --git a/lib_com/options.h b/lib_com/options.h
index c7204c05fad403821b5f831a45e0020853e976df..ad3554576e5dd6c8eeb803647b752321e83be9de 100755
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -183,6 +183,7 @@
 /* #################### Start NON-BE CR switches ########################## */
 /* any switch which is non-be wrt operation points tested in selection */
 /* all switches in this category should start with "CR_" */
+#define CR_FIX_585_MASA_2TC_DTX_EXT                     /* Nokia: issue 585: fixes transition artifacts in MASA 2TC DTX by applying correct condition */
 
 
 /* ##################### End NON-BE CR switches ########################### */
diff --git a/lib_dec/ivas_dec.c b/lib_dec/ivas_dec.c
index 2b88822d06b199f52f56cd64acbcbbe1ac071aa5..3618658b90f29f422728c5096c39810ab6977272 100644
--- a/lib_dec/ivas_dec.c
+++ b/lib_dec/ivas_dec.c
@@ -390,7 +390,11 @@ ivas_error ivas_dec(
 
         if ( st_ivas->ivas_format == MASA_FORMAT )
         {
+#ifdef CR_FIX_585_MASA_2TC_DTX_EXT
+            ivas_masa_prerender( st_ivas, output, output_frame, nchan_remapped );
+#else
             ivas_masa_prerender( st_ivas, output, output_frame );
+#endif
         }
         else if ( st_ivas->ivas_format == SBA_FORMAT && ( st_ivas->renderer_type == RENDERER_BINAURAL_PARAMETRIC || st_ivas->renderer_type == RENDERER_BINAURAL_PARAMETRIC_ROOM ) )
         {
diff --git a/lib_dec/ivas_jbm_dec.c b/lib_dec/ivas_jbm_dec.c
index 712a88f114fd9ba2b6201f3bb72933b10fb8c17b..40f077c3c8f343355de4f743bfb74ef8c65f0cc4 100644
--- a/lib_dec/ivas_jbm_dec.c
+++ b/lib_dec/ivas_jbm_dec.c
@@ -292,7 +292,11 @@ ivas_error ivas_jbm_dec_tc(
 
         if ( st_ivas->ivas_format == MASA_FORMAT )
         {
+#ifdef CR_FIX_585_MASA_2TC_DTX_EXT
+            ivas_masa_prerender( st_ivas, output, output_frame, nchan_remapped );
+#else
             ivas_masa_prerender( st_ivas, output, output_frame );
+#endif
         }
         else if ( st_ivas->ivas_format == SBA_FORMAT && ( st_ivas->renderer_type == RENDERER_BINAURAL_PARAMETRIC || st_ivas->renderer_type == RENDERER_BINAURAL_PARAMETRIC_ROOM ) )
         {
diff --git a/lib_dec/ivas_masa_dec.c b/lib_dec/ivas_masa_dec.c
index 0576fe8121f4d2ae294dca9dd52348f1ef128684..d44d81d54e438f1d2ada0b070014a73f7121b6fc 100644
--- a/lib_dec/ivas_masa_dec.c
+++ b/lib_dec/ivas_masa_dec.c
@@ -566,9 +566,17 @@ void ivas_masa_prerender(
     Decoder_Struct *st_ivas,    /* i/o: IVAS decoder handle                         */
     float output[][L_FRAME48k], /* i/o: synthesized core-coder transport channels   */
     const int16_t output_frame  /* i  : output frame length per channel             */
+#ifdef CR_FIX_585_MASA_2TC_DTX_EXT
+    ,
+    const int16_t nchan_remapped /* i  : number of transports used in core          */
+#endif
 )
 {
+#ifdef CR_FIX_585_MASA_2TC_DTX_EXT
+    if ( st_ivas->ivas_format == MASA_FORMAT && st_ivas->nchan_transport == 2 && nchan_remapped == 1 )
+#else
     if ( st_ivas->ivas_format == MASA_FORMAT && st_ivas->nchan_transport == 2 && st_ivas->hDecoderConfig->ivas_total_brate < MASA_STEREO_MIN_BITRATE )
+#endif
     {
         if ( st_ivas->hDecoderConfig->output_config == AUDIO_CONFIG_EXTERNAL )
         {