Do Peach Medallions despawn when there is smoke around them?

why are you asking this in the speedrun.com forums of all places

@boneking I didn't want to join the discord.

I was curious because this happened:

Some Peach medallions have conditions for them to appear, sometimes you need to perform certain actions, sometimes you just need to be in a specific location. My guess for this one is just it goes away to let the train engine through, but I can't really say for sure