Its not quite the same problem. Timezones are a transformation applied on top of UTC. If you are writing code, you are transforming the always increasing UTC to a more or less arbitrary dates and times.
Moving backwards means you (your code) experiences the same time twice.
It is not exactly same, but it can be framed as the same problem by requiring every nation to change their own time zone once in a while. As long as the "once in a while" is not frequent (unlikely to happen before 2500, and should happen less than once per century for next 10K years), this should be okay.
I'm always open to change my mind, but I struggle to see the relevance of that in this context.
Are there timezone areas in the world which change their UTC differential fluidly throughout the year and by the yard to pin midday to the highest position of the sun?
I'll definitely say that that'd not only surprise me but blow my mind if true!
Moving backwards means you (your code) experiences the same time twice.