Well so much for Mission 1 being better for farming regenerative oozes. I did all the deploys in them today and came up empty handed in every case. Now I don't have enough UISOs to try again until tomorrow at least.
Sometimes, after some deploys with certain characters in Mission 1, I've noticed that even before you click to see what you've gained for the reward, the task list to the left of the screen is already showing the regenerative oozes checked off, as if you're guaranteed to get one. When I have clicked on a square when this happens, I have gotten an ooze without fail, almost as if I could've clicked any square and it would've still be guaranteed. I don't know why this happens sometimes and other times not.