duplicates get stuck on non existing ladders and die

I have had this issue as well, though I saved the duplicant in question by rebuilding the ladder until they could get off of it.

Here's a screenshot, happened to me on cycle 2 of my very first colony. 

I never had situation like that. My dupes always jumps to nearby places or falls down no matter how far they have to fall.

Thanks for letting us know. Our team is working on this issue and we should hopefully have it resolved in the next build.