--- a/dom/media/TextTrack.cpp
+++ b/dom/media/TextTrack.cpp
@@ -200,27 +200,27 @@ TextTrack::UpdateActiveCueList()
     mDirty = false;
     mActiveCueList->RemoveAll();
   }
 
   double playbackTime = mediaElement->CurrentTime();
   // Remove all the cues from the active cue list whose end times now occur
   // earlier then the current playback time.
   for (uint32_t i = mActiveCueList->Length(); i > 0; i--) {
-    if ((*mActiveCueList)[i - 1]->EndTime() < playbackTime) {
+    if ((*mActiveCueList)[i - 1]->EndTime() <= playbackTime) {
       mActiveCueList->RemoveCueAt(i - 1);
     }
   }
   // Add all the cues, starting from the position of the last cue that was
   // added, that have valid start and end times for the current playback time.
   // We can stop iterating safely once we encounter a cue that does not have
   // a valid start time as the cue list is sorted.
   for (; mCuePos < mCueList->Length() &&
          (*mCueList)[mCuePos]->StartTime() <= playbackTime; mCuePos++) {
-    if ((*mCueList)[mCuePos]->EndTime() >= playbackTime) {
+    if ((*mCueList)[mCuePos]->EndTime() > playbackTime) {
       mActiveCueList->AddCue(*(*mCueList)[mCuePos]);
     }
   }
 }
 
 TextTrackCueList*
 TextTrack::GetActiveCues() {
   if (mMode != TextTrackMode::Disabled) {