diff --git a/plugins/calendar/drivers/kolab/kolab_calendar.php b/plugins/calendar/drivers/kolab/kolab_calendar.php
index 3e5d28ae..79df28a2 100644
--- a/plugins/calendar/drivers/kolab/kolab_calendar.php
+++ b/plugins/calendar/drivers/kolab/kolab_calendar.php
@@ -302,6 +302,9 @@ class kolab_calendar extends kolab_storage_folder_api
       }
     }
 
+    // avoid session race conditions that will loose temporary subscriptions
+    $this->cal->rc->session->nowrite();
+
     return $events;
   }
 
diff --git a/plugins/calendar/drivers/kolab/kolab_user_calendar.php b/plugins/calendar/drivers/kolab/kolab_user_calendar.php
index 1ab86790..dc9bcf76 100644
--- a/plugins/calendar/drivers/kolab/kolab_user_calendar.php
+++ b/plugins/calendar/drivers/kolab/kolab_user_calendar.php
@@ -222,6 +222,9 @@ class kolab_user_calendar extends kolab_calendar
       }
     }
 
+    // avoid session race conditions that will loose temporary subscriptions
+    $this->cal->rc->session->nowrite();
+
     return $events;
   }
 
diff --git a/plugins/tasklist/drivers/kolab/tasklist_kolab_driver.php b/plugins/tasklist/drivers/kolab/tasklist_kolab_driver.php
index 50fa3714..90c3048f 100644
--- a/plugins/tasklist/drivers/kolab/tasklist_kolab_driver.php
+++ b/plugins/tasklist/drivers/kolab/tasklist_kolab_driver.php
@@ -481,6 +481,9 @@ class tasklist_kolab_driver extends tasklist_driver
             }
         }
 
+        // avoid session race conditions that will loose temporary subscriptions
+        $this->plugin->rc->session->nowrite();
+
         return $counts;
     }
 
@@ -537,6 +540,9 @@ class tasklist_kolab_driver extends tasklist_driver
             }
         }
 
+        // avoid session race conditions that will loose temporary subscriptions
+        $this->plugin->rc->session->nowrite();
+
         return $results;
     }
 
diff --git a/plugins/tasklist/tasklist.js b/plugins/tasklist/tasklist.js
index 75ba3862..76d50d5e 100644
--- a/plugins/tasklist/tasklist.js
+++ b/plugins/tasklist/tasklist.js
@@ -164,7 +164,7 @@ function rcube_tasklist_ui(settings)
                 var prop = { id:p.id, active:list.active?1:0 };
                 if (list.subscribed) prop.permanent = 1;
                 rcmail.http_post('tasklist', { action:'subscribe', l:prop });
-                setTimeout(function(){ list_tasks(); }, 500);
+                list_tasks();
             }
         });