diff --git a/src/reports.c b/src/reports.c
index 48aee609d..e0d4cff37 100644
--- a/src/reports.c
+++ b/src/reports.c
@@ -1316,9 +1316,10 @@ static void prepare_reports(void)
         }
 
         for (u = r->units; u; u = u->next) {
-            if (u->building && u->building->type == bt_lighthouse) {
+            b = u->building;
+            if (b && b->type == bt_lighthouse && inside_building(u)) {
                 /* we are in a lighthouse. add the regions we can see from here! */
-                prepare_lighthouse(u->building, u->faction);
+                prepare_lighthouse(b, u->faction);
             }
 
             if (u_race(u) != get_race(RC_SPELL) || u->number == RS_FARVISION) {
@@ -1420,6 +1421,7 @@ void prepare_seen(faction *f)
 
 static void prepare_report(struct report_context *ctx, faction *f)
 {
+    assert(f->seen);
     prepare_seen(f);
     ctx->f = f;
     ctx->report_time = time(NULL);
diff --git a/src/reports.test.c b/src/reports.test.c
index c27a0f6f9..14b3c7314 100644
--- a/src/reports.test.c
+++ b/src/reports.test.c
@@ -3,6 +3,7 @@
 #include "reports.h"
 #include "report.h"
 #include "creport.h"
+#include "lighthouse.h"
 #include "move.h"
 #include "seen.h"
 #include "travelthru.h"
@@ -17,6 +18,7 @@
 #include <kernel/unit.h>
 #include <kernel/spell.h>
 #include <kernel/spellbook.h>
+#include <kernel/terrain.h>
 
 #include <util/language.h>
 #include <util/lists.h>
@@ -450,6 +452,43 @@ static void test_arg_resources(CuTest *tc) {
     test_cleanup();
 }
 
+void test_prepare_lighthouse(CuTest *tc) {
+    building *b;
+    building_type *btype;
+    unit *u;
+    region *r1, *r2;
+    faction *f;
+    const struct terrain_type *t_ocean, *t_plain;
+
+    test_setup();
+    f = test_create_faction(0);
+    t_ocean = test_create_terrain("ocean", SEA_REGION);
+    t_plain = test_create_terrain("plain", LAND_REGION);
+    btype = test_create_buildingtype("lighthouse");
+    btype->maxcapacity = 4;
+    r1 = test_create_region(0, 0, t_plain);
+    r2 = test_create_region(1, 0, t_ocean);
+    b = test_create_building(r1, btype);
+    b->flags |= BLD_MAINTAINED;
+    b->size = 10;
+    update_lighthouse(b);
+    u = test_create_unit(test_create_faction(0), r1);
+    u->number = 4;
+    u->building = b;
+    set_level(u, SK_PERCEPTION, 3);
+    CuAssertIntEquals(tc, 1, lighthouse_range(b, u->faction));
+    CuAssertPtrEquals(tc, b, inside_building(u));
+    u = test_create_unit(f, r1);
+    u->building = b;
+    set_level(u, SK_PERCEPTION, 3);
+    CuAssertIntEquals(tc, 0, lighthouse_range(b, u->faction));
+    CuAssertPtrEquals(tc, NULL, inside_building(u));
+    init_reports();
+    CuAssertPtrNotNull(tc, find_seen(f->seen, r1));
+    CuAssertPtrEquals(tc, 0, find_seen(f->seen, r2));
+    test_cleanup();
+}
+
 CuSuite *get_reports_suite(void)
 {
     CuSuite *suite = CuSuiteNew();
@@ -464,5 +503,6 @@ CuSuite *get_reports_suite(void)
     SUITE_ADD_TEST(suite, test_write_unit);
     SUITE_ADD_TEST(suite, test_write_spell_syntax);
     SUITE_ADD_TEST(suite, test_arg_resources);
+    SUITE_ADD_TEST(suite, test_prepare_lighthouse);
     return suite;
 }