I have tried searching for Flex First rewards from DUB - including via the calendar award search function, which incidentally I had never seen before.

There is no Flex First availability on dates that do not have Saver First (Z) availability, but do have plenty of revenue A available.

I think EK has removed the ability to book a Flex award in A inventory. It is still possible to book a Flex award (with increased maximum stay and free rebooking) by selecting the 'Flex' option when searching for awards, however these Flex awards are available only on dates when Z is available.

It seems the information the phone agent gave whimike is correct, all First awards now book into Z.

I'm not sure whether this is a temporary or permanent 'enhancement'...