This is an un-modded playthrough, and it looks like when half my party perished in L2 Darkest Dungeon, the game glitched and spat out a 4th talisman. Odder still, one of the talismans (the second in the picture) has an icon that rides a few pixels higher in the equipment screen, compared to the others.

Considering how often this game shafts me, I will accept this as a blessing, and continue to get slaughtered on the second foray a few more times... to a slightly lesser degree.