What counts as exploration ventures in Challenge log?

[TomTom1968]

I find it rather insulting that if you send both your retainers on exploration missions once a day, which is perfectly reasonable, you end up exactly one short of the challenge.

That's like a giant middle finger to the player.

LOL, thought the same. Even if you log in each day you will probably miss 1 exploration if you do not plan it correctly. Nice way to remind you that it is better doable if you buy some more.