diff --git a/locale.c b/locale.c
index 11465bdf5b09..718312d10a35 100644
--- a/locale.c
+++ b/locale.c
@@ -1347,7 +1347,15 @@ S_emulate_setlocale_i(pTHX_
              line, new_obj));
 
 #ifdef MULTIPLICITY
-    PL_cur_locale_obj = new_obj;
+
+    if (PL_cur_locale_obj != new_obj) {
+        DEBUG_Lv(PerlIO_printf(Perl_debug_log,
+                "(%" LINE_Tf "): PL_cur_locale_obj was %p\n", line, PL_cur_locale_obj));
+        PL_cur_locale_obj = new_obj;
+        DEBUG_Lv(PerlIO_printf(Perl_debug_log,
+                "(%" LINE_Tf "): PL_cur_locale_obj now %p\n", line, PL_cur_locale_obj));
+    }
+
 #endif
 
     /* We are done, except for updating our records (if the system doesn't keep
@@ -1422,6 +1430,10 @@ S_stdize_locale(pTHX_ const int category,
 
     PERL_ARGS_ASSERT_STDIZE_LOCALE;
 
+    DEBUG_Lv(PerlIO_printf(Perl_debug_log,
+                          "(%" LINE_Tf "): Entering stdize_locale(%d, '%s')\n",
+                          caller_line, category, input_locale));
+
     if (input_locale == NULL) {
         return NULL;
     }
@@ -2910,6 +2922,12 @@ S_get_locale_string_utf8ness_i(pTHX_ const char * string,
      * use the current locale for the category specified by 'cat_index'.
      */
 
+    DEBUG_Lv(PerlIO_printf(Perl_debug_log,
+                           "Entering get_locale_string_utf8ness_i; locale=%s,"
+                           " index=%u(%s), string=%s, known_utf8=%d\n",
+                           locale, cat_index, category_names[cat_index],
+                           _byte_dump_string((U8 *) string, strlen(string), 0),
+                           known_utf8));
     if (string == NULL) {
         return UTF8NESS_NO;
     }