I don't know if this is the case for you but sometimes what happens
is that the list is preloaded for 30 pokem/eggs and by the time you
get around to actually clicking, it's already hatched and released
by the owner, meaning that the interaction dies not count.
I've especially noticed this on fast interaction days when people
are fast about refilling their parties.
Please train with my shadow wartortle. He's so cute!