ChoiceScript Save Plugin is an amazing tool! Especially because I play IF games online, but there is one small nuance. Saves are unstable, can disappear, etc., and you don’t always want to replay long games. That’s why the question arose. Is there a script, but with the ability to import and export your saves to PC?
I’d love to know this too, I’m getting a few comments about the saves becoming weird lately… 
Apologies for missing the first message but I assume what you’re both encountering is invalidated saves during active development.
Saves ultimately need to store relevant game state, in order to be able to “restore” it. During development what you’d consider “relevant game state” will probably change over time, often dramatically. You’ll add new variables, rename others and pad out scenes or even remove them entirely. Meaning that saves from older versions can restore a state that doesn’t make sense in the new version of the game. This can lead to “weird” behaviour.
It’s very difficult to create a save system that will function properly 100% of the time, without knowing intimate details about the game internals and how it’s changed between save versions. You could, for example, detect “old” saves and “fill in” or modify them to match the new/expected relevant state - but that would need to be done on a per-game basis, by the game author.
If your game is finished and your changes are minimal, then saves shouldn’t be quite so weird.