diff --git a/src/symbols.c b/src/symbols.c
index 0b517addd..6867bb425 100644
--- a/src/symbols.c
+++ b/src/symbols.c
@@ -7,6 +7,7 @@
 
 static void savedsym_add(const char *, const char *, int);
 static struct _savedsym *savedsym_find(const char *, int);
+void purge_custom_entries(enum graphics_sets which_set);
 
 extern const uchar def_r_oc_syms[MAXOCLASSES];      /* drawing.c */
 
@@ -332,6 +333,10 @@ clear_symsetentry(int which_set, boolean name_too)
             free((genericptr_t) g.symset[which_set].name);
         g.symset[which_set].name = (char *) 0;
     }
+#ifdef ENHANCED_SYMBOLS
+    free_all_glyphmap_u();
+    purge_custom_entries(which_set);
+#endif
 }
 
 boolean symset_is_compatible(enum symset_handling_types handling, unsigned long wincap2)
@@ -462,7 +467,11 @@ parse_sym_line(char *buf, int which_set)
     symp = match_sym(buf);
     if (!symp && buf[0] == 'G' && buf[1] == '_') {
 #ifdef ENHANCED_SYMBOLS
-        is_glyph = match_glyph(buf);
+        if (g.chosen_symset_start) {
+            is_glyph = match_glyph(buf);
+        } else {
+            is_glyph = TRUE; /* report error only once */
+        }
 #else
         enhanced_unavailable = TRUE;
 #endif
@@ -608,7 +617,9 @@ parse_sym_line(char *buf, int which_set)
                 }
 #ifdef ENHANCED_SYMBOLS
             } else {
-                glyphrep_to_custom_map_entries(buf, &glyph);
+                if (g.chosen_symset_start) {
+                    glyphrep_to_custom_map_entries(buf, &glyph);
+                }
 #endif
             }
         }
@@ -1047,7 +1058,6 @@ struct customization_detail *find_matching_symset_customization(
     enum graphics_sets which_set);
 struct customization_detail *find_display_urep_customization(
     const char *customization_name, int glyphidx, enum graphics_sets which_set);
-void purge_custom_entries(enum graphics_sets which_set);
 extern glyph_map glyphmap[MAX_GLYPH];
 static void shuffle_customizations(void);
 
@@ -1058,11 +1068,11 @@ apply_customizations_to_symset(enum graphics_sets which_set)
     struct customization_detail *details;
 
     if (g.symset[which_set].handling == H_UTF8
-        && g.sym_customizations[UNICODESET].count
-        && g.sym_customizations[UNICODESET].details) {
+        && g.sym_customizations[which_set].count
+        && g.sym_customizations[which_set].details) {
         /* These UTF-8 customizations get applied to the glyphmap array,
            not to symset entries */
-        details = g.sym_customizations[UNICODESET].details;
+        details = g.sym_customizations[which_set].details;
         while (details) {
             gm = &glyphmap[details->content.urep.glyphidx];
             (void) set_map_u(gm,
@@ -1080,18 +1090,51 @@ apply_customizations_to_symset(enum graphics_sets which_set)
 static void
 shuffle_customizations(void)
 {
-    int i;
-    struct unicode_representation *tmp_u[2][NUM_OBJECTS];
+    static const int offsets[2] = { GLYPH_OBJ_OFF, GLYPH_OBJ_PILETOP_OFF };
+    int j;
 
-    for (i = 0; i < NUM_OBJECTS; i++) {
-        tmp_u[0][i] =
-            glyphmap[objects[i].oc_descr_idx + GLYPH_OBJ_OFF].u;
-        tmp_u[1][i] =
-            glyphmap[objects[i].oc_descr_idx + GLYPH_OBJ_PILETOP_OFF].u;
-    }
-    for (i = 0; i < NUM_OBJECTS; i++) {
-        glyphmap[i + GLYPH_OBJ_OFF].u = tmp_u[0][i];
-        glyphmap[i + GLYPH_OBJ_PILETOP_OFF].u = tmp_u[1][i];
+    for (j = 0; j < SIZE(offsets); j++) {
+        glyph_map *obj_glyphs = glyphmap + offsets[j];
+        int i;
+        struct unicode_representation *tmp_u[NUM_OBJECTS];
+        int duplicate[NUM_OBJECTS];
+
+        for (i = 0; i < NUM_OBJECTS; i++) {
+            duplicate[i] = -1;
+        }
+        for (i = 0; i < NUM_OBJECTS; i++) {
+            int idx = objects[i].oc_descr_idx;
+
+            /*
+             * Shuffling gem appearances can cause the same oc_descr_idx to
+             * appear more than once. Detect this condition and ensure that
+             * each pointer points to a unique allocation.
+             */
+            if (duplicate[idx] >= 0) {
+                /* Current structure already appears in tmp_u */
+                struct unicode_representation *other = tmp_u[duplicate[idx]];
+
+                tmp_u[i] = (struct unicode_representation *) alloc(sizeof *tmp_u[i]);
+                *tmp_u[i] = *other;
+                if (other->utf8str != NULL) {
+                    tmp_u[i]->utf8str = (uint8 *) dupstr((const char *) other->utf8str);
+                }
+            } else {
+                tmp_u[i] = obj_glyphs[idx].u;
+                if (obj_glyphs[idx].u != NULL)  {
+                    duplicate[idx] = i;
+                    obj_glyphs[idx].u = NULL;
+                }
+            }
+        }
+        for (i = 0; i < NUM_OBJECTS; i++) {
+            /* Some glyphmaps may not have been transferred */
+            if (obj_glyphs[i].u != NULL) {
+                free(obj_glyphs[i].u->utf8str);
+                free(obj_glyphs[i].u);
+            }
+            obj_glyphs[i].u = tmp_u[i];
+        }
     }
 }
 
@@ -1112,7 +1155,7 @@ purge_custom_entries(enum graphics_sets which_set)
 {
     struct symset_customization *gdc = &g.sym_customizations[which_set];
     struct customization_detail *details = gdc->details, *next;
-    if (details) {
+    while (details) {
         next = details->next;
         if (gdc->custtype == custom_ureps) {
             if (details->content.urep.u.utf8str)
diff --git a/src/utf8map.c b/src/utf8map.c
index fbffe18b7..35e390fbb 100644
--- a/src/utf8map.c
+++ b/src/utf8map.c
@@ -65,7 +65,7 @@ to_custom_symset_entry_callback(int glyph, struct find_struct *findwhat)
                   (findwhat->color != 0L) ? findwhat->color : 0L);
 #endif
         add_custom_urep_entry(known_handling[H_UTF8], glyph,
-                              uval, utf8str, findwhat->color, UNICODESET);
+                              uval, utf8str, findwhat->color, g.symset_which_set);
     }
 }