Thank you!

This issue has been reported to the programmers. I have also listed this thread here: 🌟 📜 Achievement Related Bugs

Sooo, apparently this isn't a bug:

Achievements aren't glitched. You either get one, or the other. If on your first go you cannot get 25 ghosts in 30 seconds, you are given a second chance, with fewer ghosts. The reward is the same, as it's for completing the plot step more than anything. There is just a little extra ~prestige~ in getting the 25 ghosts.

Since this isn't a bug I am going to lock up this thread. If you wish to discuss the topic further please check out the Feedback forum.