Originally posted by FeanorsCurse:

Hey guys, thanks a lot for the helpful comments. We're playing vanilla, and have explored new area pretty far from the start, so I'm not sure what's wrong there. But I'm gonna try the Upgrade World mod to refresh. Thanks!

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https://prnt.sc/mdc0devKwg3W

Hey guys, thanks a lot for the helpful comments. We're playing vanilla, and have explored new area pretty far from the start, so I'm not sure what's wrong there. But I'm gonna try the Upgrade World mod to refresh. Thanks!

Just to note about using the map generator, in case you were unaware, in order for it to accurately give you a map based on your currently existing seed, you have to upload your world files (the blue upload button next to the text box); it provides instructions for this. If you just enter your seed code (number?), it generates a map under the assumption it's a brand new, completely unexplored world, which is why you would be seeing frost cave markers on the generated map but not finding any in your world.

Also, if you have unexplored mountains, but have explored the area surrounding them - PRIOR to the update - the actual world generation area is much larger than what is revealed by the player. This means the mountain could have already been fully generated before the patch and thus wouldn't be able to update to spawn caves.
There is a mod, Upgrade World, that can regenerate the mountain biome and enable the caves to spawn. Obviously you'd use this at your own risk and you'll want to be sure to backup your world files beforehand. I've used it for this with no issues so far.

Do you use mods? I play vanilla and haven't had any trouble finding mountain caves in new areas. So, either you explored closer to those mountains than you think, or you have mods interfering--or you have a borked world and may need to restart (though I think there is something that will let you reset the biomes, but it's in the mod category so I don't bother with it).