diff --git a/src/report.c b/src/report.c
index 64febfb44..c7093da73 100644
--- a/src/report.c
+++ b/src/report.c
@@ -1951,7 +1951,7 @@ static void init_cb(cb_data *data, stream *out, char *buffer, size_t size, const
     data->counter = 0;
 }
 
-static void cb_write_travelthru(const region *r, unit *u, void *cbdata) {
+static void cb_write_travelthru(region *r, unit *u, void *cbdata) {
     cb_data *data = (cb_data *)cbdata;
     const faction *f = data->f;
 
@@ -2006,7 +2006,7 @@ static void cb_write_travelthru(const region *r, unit *u, void *cbdata) {
     }
 }
 
-void write_travelthru(stream *out, const region *r, const faction *f)
+void write_travelthru(stream *out, region *r, const faction *f)
 {
     int maxtravel;
     char buf[8192];
@@ -2038,7 +2038,7 @@ report_plaintext(const char *filename, report_context * ctx,
     int flag = 0;
     char ch;
     int anyunits, no_units, no_people;
-    const struct region *r;
+    region *r;
     faction *f = ctx->f;
     unit *u;
     char pzTime[64];
diff --git a/src/report.h b/src/report.h
index ec0ee903c..84a6c66d4 100644
--- a/src/report.h
+++ b/src/report.h
@@ -27,7 +27,7 @@ extern "C" {
     void register_nr(void);
     void report_cleanup(void);
     void write_spaces(struct stream *out, size_t num);
-    void write_travelthru(struct stream *out, const struct region * r, const struct faction * f);
+    void write_travelthru(struct stream *out, struct region * r, const struct faction * f);
 
     void nr_spell_syntax(struct stream *out, struct spellbook_entry * sbe, const struct locale *lang);
     void nr_spell(struct stream *out, struct spellbook_entry * sbe, const struct locale *lang);
diff --git a/src/reports.c b/src/reports.c
index cdf85d096..50e220393 100644
--- a/src/reports.c
+++ b/src/reports.c
@@ -971,7 +971,7 @@ typedef struct address_data {
     int stealthmod;
 } address_data;
 
-static void cb_add_address(const region *r, unit *ut, void *cbdata) {
+static void cb_add_address(region *r, unit *ut, void *cbdata) {
     address_data *data = (address_data *)cbdata;
     faction *f = data->f;
 
@@ -1292,10 +1292,11 @@ static region *firstregion(faction * f)
 #endif
 }
 
-static void cb_add_seen(const region *rc, unit *u, void *cbdata) {
-    region *r = (region *)cbdata;
-    assert(rc == r);
-    faction_add_seen(u->faction, r, seen_travel);
+static void cb_add_seen(region *r, unit *u, void *cbdata) {
+    faction *f = (faction *)cbdata;
+    if (u->faction==f) {
+        faction_add_seen(f, r, seen_travel);
+    }
 }
 
 /** set region.seen based on visibility by one faction.
@@ -1359,7 +1360,7 @@ void prepare_report(report_context *ctx, faction *f)
         }
 
         if (fval(r, RF_TRAVELUNIT)) {
-            travelthru_map(r, cb_add_seen, r);
+            travelthru_map(r, cb_add_seen, f);
         }
     }
     // [fast,last) interval of seen regions (with lighthouses and travel)
@@ -2062,7 +2063,7 @@ typedef struct count_data {
     const struct faction *f;
 } count_data;
 
-static void count_cb(const region *r, unit *u, void *cbdata) {
+static void count_cb(region *r, unit *u, void *cbdata) {
     count_data *data = (count_data *)cbdata;
     const struct faction *f = data->f;
     if (r != u->region && (!u->ship || ship_owner(u->ship) == u)) {
@@ -2072,7 +2073,7 @@ static void count_cb(const region *r, unit *u, void *cbdata) {
     }
 }
 
-int count_travelthru(const struct region *r, const struct faction *f) {
+int count_travelthru(struct region *r, const struct faction *f) {
     count_data data = { 0 };
     data.f = f;
     travelthru_map(r, count_cb, &data);
diff --git a/src/reports.h b/src/reports.h
index 3c4a86707..fd0efb591 100644
--- a/src/reports.h
+++ b/src/reports.h
@@ -125,7 +125,7 @@ extern "C" {
 
     int stream_printf(struct stream * out, const char *format, ...);
 
-    int count_travelthru(const struct region *r, const struct faction *f);
+    int count_travelthru(struct region *r, const struct faction *f);
 
 #define GR_PLURAL     0x01      /* grammar: plural */
 #define MAX_INVENTORY 128       /* maimum number of different items in an inventory */
diff --git a/src/travelthru.c b/src/travelthru.c
index deaa05f27..32607ae5c 100644
--- a/src/travelthru.c
+++ b/src/travelthru.c
@@ -95,7 +95,7 @@ bool travelthru_cansee(const struct region *r, const struct faction *f, const st
     return false;
 }
 
-void travelthru_map(const region * r, void(*cb)(const region *, struct unit *, void *), void *cbdata)
+void travelthru_map(region * r, void(*cb)(region *, struct unit *, void *), void *cbdata)
 {
     attrib *a;
     assert(r);
diff --git a/src/travelthru.h b/src/travelthru.h
index 44c6e3978..4e43dd25a 100644
--- a/src/travelthru.h
+++ b/src/travelthru.h
@@ -11,7 +11,7 @@ extern "C" {
     struct region;
     struct faction;
     struct unit;
-    void travelthru_map(const struct region * r, void(*cb)(const struct region *r, struct unit *, void *), void *cbdata);
+    void travelthru_map(struct region * r, void(*cb)(struct region *r, struct unit *, void *), void *cbdata);
     bool travelthru_cansee(const struct region *r, const struct faction *f, const struct unit *u);
     void travelthru_add(struct region * r, struct unit * u);
 
diff --git a/src/travelthru.test.c b/src/travelthru.test.c
index 06a3633ab..74ab29b7e 100644
--- a/src/travelthru.test.c
+++ b/src/travelthru.test.c
@@ -13,7 +13,7 @@
 
 struct attrib;
 
-static void count_travelers(const region *r, unit *u, void *cbdata) {
+static void count_travelers(region *r, unit *u, void *cbdata) {
     int *n = (int *)cbdata;
     unused_arg(r);
     *n += u->number;