Cheats shouldn't make a difference. One issue is that the game uses your browser's local storage to save data. So depending on the browser, it can have issues if there are too many things running / taking memory. I find the best luck with Chrome, sometimes I have to clear the cache beforehand.
It's probably an issue like this. We have put in some work to try and ensure save files stay under 1MB (I checked and my current 40-day save is 500kb), but it's not perfect, and sometimes people will still encounter browser issues for various reasons. I had to hack the Harlowe engine to stop tracking variables changing every "passage", because these were growing indefinitely. These constantly growing variables may be why other Harlowe games like Transylvania are having more consistent save issues, but not 100% sure.
It's always safest to export your save data to a file. This is not normally something Twine Harlowe can do but we also hacked in this feature
Eventually we will try exporting and packaging this game as an electron app, which should give us the ability to have more storage and system resources. But at present, X-Change Life has to compete with whatever else is stored on your browser to stash its ~500kb-1mb save data.