You will get these quests again when you reach VFI heard about something similar in another age. There seem to be some points in the story quest line when it just vanishes if you are not progressed far enough in research or map. It will pop up again at a later point when you researched a specific quest or reached a specific point on the map.
there are indeed such points in the game. When you have made sufficient progress through the game the next story quest will trigger. Accordingly I will set this thread to not a bug. However, if you would like further reassurance that there is nothing amiss with your quests in particular, please do contact our support team, so that they can take a closer look at those quests for you.There seem to be some points in the story quest line when it just vanishes if you are not progressed far enough in research or map.