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Incorrect
The link expires after 15 minutesIs 15 minutes enough?.
The link expires after :comment[15 minutes]{#ttl note="Is 15 minutes enough?"}.
:comment{reply="tll" note="Keeping 15."}Correct
The link expires after 15 minutesIs 15 minutes enough?Keeping 15..
The link expires after :comment[15 minutes]{#ttl note="Is 15 minutes enough?"}.
:comment{reply="ttl" note="Keeping 15."}