The delayed triggered ability generated by Glorious End waits for the next actual End step of yours to occur. No End step occurred this turn because of Sundial, but you still have this delayed trigger, lurking in the mists, to worry about, until it triggers.
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Because it can be relevant, if you end the turn *during* the end step (and, thus, with the "lose the game" trigger on the stack), it will not trigger again. It will be exiled when the turn is ended so you still won't lose, but it is important to note that letting it trigger and ending the turn prevents you from losing and prevents it from triggering again.
You used glorious end on the turn before this, and it was waiting to trigger on your end step.
Does the trigger occur on your next end step as the previous end step was skipped?
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