You might have seen me or others posting on Twitter about insurance contacts, bonus points, and extra credit contacts. It's an "inside joke" among satellite operators who are chasing UT1FG/MM as he traverses through wet grid squares in the open ocean.
Basically, it boils down to this:
Maybe the bird was low, you didn't hear Yuri's return QSL, or maybe Yuri was very weak into the satellite. There are sometimes legitimate reasons why someone might try to work Yuri in the same grid again if their first contact was "iffy." Just be sure to make your "insurance" contact as quickly as efficiently as possible. Sometimes Yuri will even comment "Thanks again for contact from grid FKxx after we worked on AO-7." He is basically saying "I got you in the log on that one" and may even subtly mentioning "WHY ARE YOU CALLING AGAIN?" He being a gentleman and a top class operator never loses his cool even with bad behavior from some operators.
It's like "Hey Bro -- We know you are out there and we want you to know we want more grids from you." Many times those seeking bonus points or extra credit already have the grid confirmed. While it's entirely their right to make the QSO again, you have to bear in mind the rarity of the operation at hand. If there is a satellite pass where Yuri is CQ'ing for 5 minutes straight, chances are you have time to make a bonus QSO without jeopardizing someone else making the cut. Also keep footprints in mind. You may think nobody is in the footprint working Yuri, but as the orbit progresses it will potentially pickup more land coverage where others might be who want to work Yuri. Just be cognizant of this and not try to tie up the captain for extended periods.