There is an insidious bug that will lead to the game crashing whenever you have a random encounter while traveling on the world map. What's worse, once this bug is triggered, it is preserved in saves you make from then on.

Fortunately, the trigger was figured out by fans and can be avoided: this bug is set off when you use the Mystic Magnets to teleport back to your room from a "random location" (any location on the map not represented by an icon).

It's possible, though doubtful, that the bug can also be set off by using the Magnets from the overhead travel map. If you want to be 100% safe, just make sure to head for the nearest Dragon Pillar/other unique location, if you aren't at one already, when you want to use your Mystic Magnet.