#1 is correct - Someone was currently gifting me subs. I knew it, but the time machine didn't (appropriately) because they were trying to hide the fact from other players so they used their time machine to change it to a gift at the last moment.
With a button for Max available sub, then however many are ready at that point in time go to the destination set.
For instance, I have an outpost with 12 subs, 10 shield. Someone is sending 12 to the base, to be turned into a gift at the last minute. I know they are doing this, they have been doing it for days. When I scroll forward to after the time they arrive, Time Machine thinks I have 10 drillers and no shields, when I will instead have 24 drillers and 10 shields. I don't want the time machine to tell me anything different, just a button to choose All the drillers that are available at that point in time.
If they keep gifting, it will be 24, if they turn against me, it would be 10. As it currently works, I cannot queue more than 10 in the time machine for that point in time.
Hope that makes sense.