Upon completing a levequest, an aetherial node appears and grants you the reward(s) from the levequest
After a set amount of time, the node disappears, but the rewards can still be obtained by selecting any Aetheryte

With company leves, if the node vanishes, you can touch any Aetheryte to receive the money, however, the company seals are completely lost. There is no way to get them, at all

I know the obvious answer is "Touch the node before it fades"
But one of the company leves is to kill 2 each of three different MOBs....
And killing 4 of each MOB gets you a 10 seal bonus....
But once you get to 4 of each, the leve doesn't stop... you must still wait out the entire leve duration (Which in itself is stupid). Killing more than 4 of any of the MOBs does absolutely nothing... So why not go AFK once you get to 4 of each MOB killed

At any rate... It seems to be a bug in which you cannot claim seal rewards if you miss the leve completion node