I feel like they will leave after this should be accepted, am i right?
It says the translation is: They will be leaving in 1 hour. Maybe a glitch.
It is quite difficult to distinguish between "an dèidh" and "an-dè" on this audio - so I got it wrong! :(
Just done it again and they will leave after this isn't acceptes
As Rebekah417138 said below, they are two different tenses.
I think it may be something to do with the tense of the verb - "they will leave" and "they will be leaving" are, technically, two different tenses of the verb "to be" (if I am correct). I hope that helps.