diff --git a/src/db/db/dbPropertiesRepository.cc b/src/db/db/dbPropertiesRepository.cc
index 3f3d10049c..3d6628fe70 100644
--- a/src/db/db/dbPropertiesRepository.cc
+++ b/src/db/db/dbPropertiesRepository.cc
@@ -89,6 +89,11 @@ PropertiesRepository::prop_name_id (const tl::Variant &name)
 void 
 PropertiesRepository::change_properties (property_names_id_type id, const properties_set &new_props)
 {
+  //  NOTE: change_properties MAY put the property map into a state where there is
+  //  more than one property ID per set. For example, 1 and 5 may be valid property
+  //  ids for the same set. "properties(1)" and "properties(5)" returns the same
+  //  property set "S", while "properties_id(S)" only returns 1.
+
   const properties_set &old_props = properties (id);
 
   std::map <properties_set, properties_id_type>::const_iterator pi = m_properties_ids_by_set.find (old_props);
@@ -149,7 +154,10 @@ PropertiesRepository::properties_id (const properties_set &props)
   std::map <properties_set, properties_id_type>::const_iterator pi = m_properties_ids_by_set.find (props);
   if (pi == m_properties_ids_by_set.end ()) {
 
-    properties_id_type id = m_properties_ids_by_set.size ();
+    properties_id_type id = 0;
+    if (! m_properties_by_id.empty ()) {
+      id = (--m_properties_by_id.end ())->first + 1;
+    }
     m_properties_ids_by_set.insert (std::make_pair (props, id));
     m_properties_by_id.insert (std::make_pair (id, props));
     for (properties_set::const_iterator nv = props.begin (); nv != props.end (); ++nv) {
diff --git a/src/plugins/streamers/oasis/unit_tests/dbOASISReaderTests.cc b/src/plugins/streamers/oasis/unit_tests/dbOASISReaderTests.cc
index ae287e6f07..a519ff1a7f 100644
--- a/src/plugins/streamers/oasis/unit_tests/dbOASISReaderTests.cc
+++ b/src/plugins/streamers/oasis/unit_tests/dbOASISReaderTests.cc
@@ -639,6 +639,31 @@ TEST(Bug_1474)
   }
 }
 
+TEST(Bug_1799)
+{
+  db::Manager m (false);
+  db::Layout layout (&m);
+
+  {
+    tl::InputStream file (tl::testdata () + "/oasis/issue_1799.oas");
+    db::OASISReader reader (file);
+    reader.read (layout);
+  }
+
+  db::properties_id_type pn = layout.properties_repository ().prop_name_id (tl::Variant (1));
+  db::PropertiesRepository::properties_set ps;
+  ps.insert (std::make_pair (pn, tl::Variant ("hello, world!")));
+
+  auto pid = layout.properties_repository ().properties_id (ps);
+
+  auto ps2 = layout.properties_repository ().properties (pid);
+  EXPECT_EQ (ps2.size (), size_t (1));
+  EXPECT_EQ (ps2.find (pn) != ps2.end (), true);
+  if (ps2.find (pn) != ps2.end ()) {
+    EXPECT_EQ (ps2.find (pn)->second.to_string (), "hello, world!");
+  }
+}
+
 TEST(DuplicateCellname)
 {
   db::Manager m (false);
diff --git a/testdata/oasis/issue_1799.oas b/testdata/oasis/issue_1799.oas
new file mode 100644
index 0000000000..32ae303d8b
Binary files /dev/null and b/testdata/oasis/issue_1799.oas differ