diff --git a/src/base/bittorrent/torrenthandle.cpp b/src/base/bittorrent/torrenthandle.cpp
index bb75083b6..97b355c32 100644
--- a/src/base/bittorrent/torrenthandle.cpp
+++ b/src/base/bittorrent/torrenthandle.cpp
@@ -1136,6 +1136,8 @@ qlonglong TorrentHandle::timeSinceUpload() const
 #if (LIBTORRENT_VERSION_NUM < 10200)
     return m_nativeStatus.time_since_upload;
 #else
+    if (m_nativeStatus.last_upload.time_since_epoch().count() == 0)
+        return -1;
     return lt::total_seconds(lt::clock_type::now() - m_nativeStatus.last_upload);
 #endif
 }
@@ -1145,6 +1147,8 @@ qlonglong TorrentHandle::timeSinceDownload() const
 #if (LIBTORRENT_VERSION_NUM < 10200)
     return m_nativeStatus.time_since_download;
 #else
+    if (m_nativeStatus.last_download.time_since_epoch().count() == 0)
+        return -1;
     return lt::total_seconds(lt::clock_type::now() - m_nativeStatus.last_download);
 #endif
 }
diff --git a/src/webui/api/serialize/serialize_torrent.cpp b/src/webui/api/serialize/serialize_torrent.cpp
index 4f3423fff..14c7935bc 100644
--- a/src/webui/api/serialize/serialize_torrent.cpp
+++ b/src/webui/api/serialize/serialize_torrent.cpp
@@ -136,9 +136,9 @@ QVariantMap serialize(const BitTorrent::TorrentHandle &torrent)
         ret[KEY_TORRENT_LAST_ACTIVITY_TIME] = 0;
     }
     else {
-        QDateTime dt = QDateTime::currentDateTime();
-        dt = dt.addSecs(-torrent.timeSinceActivity());
-        ret[KEY_TORRENT_LAST_ACTIVITY_TIME] = dt.toSecsSinceEpoch();
+        const qint64 dt = (QDateTime::currentDateTime().toSecsSinceEpoch()
+            - torrent.timeSinceActivity());
+        ret[KEY_TORRENT_LAST_ACTIVITY_TIME] = dt;
     }
 
     return ret;