Okay, so awhile back, I slotted in the KDF DOFF mission "Answer a Subordinate's Challenge" and went off my way. Came back a little later and, as I'm clearing my DOFFs, I come to notice that the timer for the next DOFF completion was -2 hours. Go to check and that mission was stuck on "Completing". Tried to Abort the mission, but it refused.
As of this writing, it's been nearly 3 and a half hours since it finished. Something up?
EDIT: Cancel this. Took about 7 hours, but it rattled itself free.