diff --git a/src/btle/btle_hub.cpp b/src/btle/btle_hub.cpp
index 557a2867..e436ca4b 100644
--- a/src/btle/btle_hub.cpp
+++ b/src/btle/btle_hub.cpp
@@ -88,11 +88,12 @@ void BtleHub::connectToDevice(const QBluetoothDeviceInfo &device)
     }
 
     // Clean up any previously-created service objects
-    delete m_hrService;    m_hrService    = nullptr;
-    delete m_cscService;   m_cscService   = nullptr;
-    delete m_powerService; m_powerService = nullptr;
-    delete m_ftmsService;  m_ftmsService  = nullptr;
-    delete m_moxyService;  m_moxyService  = nullptr;
+    delete m_hrService;       m_hrService       = nullptr;
+    delete m_cscService;      m_cscService      = nullptr;
+    delete m_powerService;    m_powerService    = nullptr;
+    delete m_ftmsService;     m_ftmsService     = nullptr;
+    delete m_moxyService;     m_moxyService     = nullptr;
+    delete m_batteryService;  m_batteryService  = nullptr;
 
     m_firstCscMeasurement   = true;
     m_ftmsControlRequested  = false;
diff --git a/src/model/account.cpp b/src/model/account.cpp
index 3dcb43ed..43e2c90d 100644
--- a/src/model/account.cpp
+++ b/src/model/account.cpp
@@ -53,8 +53,8 @@ Account::Account(QObject *parent) : QObject(parent)  {
     intervals_icu_refresh_token = settings.value("intervals_icu_refresh_token", "").toString();
     // Sensor dropout auto-pause
     sensor_dropout_enabled   = settings.value("sensor_dropout_enabled",   true).toBool();
-    sensor_dropout_timeout_s = settings.value("sensor_dropout_timeout_s", 5   ).toInt();
-    battery_warning_threshold = settings.value("battery_warning_threshold", 20).toInt();
+    sensor_dropout_timeout_s = qBound(2, settings.value("sensor_dropout_timeout_s", 5).toInt(), 30);
+    battery_warning_threshold = qBound(5, settings.value("battery_warning_threshold", 20).toInt(), 50);
     settings.endGroup();
 
     // Load encrypted third-party service credentials from the platform credential store.
@@ -165,8 +165,8 @@ Account::Account(QObject *parent) : QObject(parent)  {
         QSettings s;
         s.beginGroup("account");
         interval_summary_enabled    = s.value("interval_summary_enabled",    true).toBool();
-        interval_summary_duration_s = s.value("interval_summary_duration_s", 5).toInt();
-        app_theme = s.value("app_theme", 2).toInt(); // default: System
+        interval_summary_duration_s = qBound(2, s.value("interval_summary_duration_s", 5).toInt(), 15);
+        app_theme = qBound(0, s.value("app_theme", 2).toInt(), 2); // default: System
         s.endGroup();
     }
 
@@ -258,7 +258,7 @@ void Account::saveSensorDropoutSettings()
     QSettings settings;
     settings.beginGroup("account");
     settings.setValue("sensor_dropout_enabled",   sensor_dropout_enabled);
-    settings.setValue("sensor_dropout_timeout_s", sensor_dropout_timeout_s);
+    settings.setValue("sensor_dropout_timeout_s", qBound(2, sensor_dropout_timeout_s, 30));
     settings.endGroup();
 }
 
@@ -266,7 +266,7 @@ void Account::saveBatteryWarningThreshold()
 {
     QSettings settings;
     settings.beginGroup("account");
-    settings.setValue("battery_warning_threshold", battery_warning_threshold);
+    settings.setValue("battery_warning_threshold", qBound(5, battery_warning_threshold, 50));
     settings.endGroup();
 }
 
@@ -275,7 +275,7 @@ void Account::saveIntervalSummarySettings()
     QSettings settings;
     settings.beginGroup("account");
     settings.setValue("interval_summary_enabled",    interval_summary_enabled);
-    settings.setValue("interval_summary_duration_s", interval_summary_duration_s);
+    settings.setValue("interval_summary_duration_s", qBound(2, interval_summary_duration_s, 15));
     settings.endGroup();
 }
 
@@ -283,7 +283,7 @@ void Account::saveAppTheme()
 {
     QSettings s;
     s.beginGroup("account");
-    s.setValue("app_theme", app_theme);
+    s.setValue("app_theme", qBound(0, app_theme, 2));
     s.endGroup();
 }
 
diff --git a/src/ui/mainwindow.cpp b/src/ui/mainwindow.cpp
index 8b44e5f2..c5cb7415 100644
--- a/src/ui/mainwindow.cpp
+++ b/src/ui/mainwindow.cpp
@@ -719,8 +719,13 @@ void MainWindow::tryAdvanceWorkoutQueue()
     const QString nextName = m_workoutQueue->name(0);
     const QString nextPath = m_workoutQueue->filePath(0);
     WorkoutCountdownDialog countdown(nextName, 60, this);
-    if (countdown.exec() != QDialog::Accepted)
+    if (countdown.exec() != QDialog::Accepted) {
+        // User chose "Cancel Queue" — clear the remaining queue so it doesn't
+        // auto-advance after subsequent workouts.
+        if (countdown.dialogResult() == WorkoutCountdownDialog::Result::Cancelled)
+            m_workoutQueue->clear();
         return;
+    }
 
     // Defer via singleShot so this stack frame fully unwinds before
     // the next workout begins — avoids unbounded recursion with long queues.
diff --git a/src/ui/pmcdialog.cpp b/src/ui/pmcdialog.cpp
index ee2f3792..83c9034b 100644
--- a/src/ui/pmcdialog.cpp
+++ b/src/ui/pmcdialog.cpp
@@ -78,7 +78,7 @@ void PmcDialog::setupUi(const QList<PmcPoint> &points)
 
     // ── close button ──────────────────────────────────────────────────────────
     auto *buttons = new QDialogButtonBox(QDialogButtonBox::Close, this);
-    connect(buttons, &QDialogButtonBox::rejected, this, &QDialog::accept);
+    connect(buttons, &QDialogButtonBox::rejected, this, &QDialog::reject);
 
     // ── layout ────────────────────────────────────────────────────────────────
     auto *mainLayout = new QVBoxLayout(this);