It'll take me a while to reproduce this, but here's what I'm fairly sure happened:
I'd unlocked South Pacific and was wandering around there trying to amass the 30 investigation points to raise Ryleh. One of my characters had 16 trophies, so I tried to buy one of the Cthulhu relics from the ship shop. Instead of getting one of the relics, I received 6 investigation points; and I'm fairly sure lost all 15 trophies that the relic would have cost. Has anyone else experienced this? Am I hallucinating and it really only cost me 4 trophies (and the game won't let you buy a relic until Ryleh rises)?