diff --git a/components/script/timers.rs b/components/script/timers.rs
index 75e044421ea..b86bdc17aae 100644
--- a/components/script/timers.rs
+++ b/components/script/timers.rs
@@ -229,7 +229,9 @@ impl OneshotTimers {
 
     pub fn suspend(&self) {
         // Suspend is idempotent: do nothing if the timers are already suspended.
-        if self.suspended_since.get().is_some() { return; }
+        if self.suspended_since.get().is_some() {
+            return warn!("Suspending an already suspended timer.");
+        }
 
         self.suspended_since.set(Some(precise_time_ms()));
         self.invalidate_expected_event_id();
@@ -239,7 +241,7 @@ impl OneshotTimers {
         // Suspend is idempotent: do nothing if the timers are already suspended.
         let additional_offset = match self.suspended_since.get() {
             Some(suspended_since) => precise_time_ms() - suspended_since,
-            None => return,
+            None => return warn!("Resuming an already resumed timer."),
         };
 
         self.suspension_offset.set(self.suspension_offset.get() + additional_offset);