Flashcards' card-next-schedule is set to strange dates

Some of my flashcards weren’t appearing when I expected so I had a look in the files, after seeing some strange dates I wrote a script to find which years card-next-schedule is being set to. This is the result:

2024 2025 2026 2027 2028 2029 2030 2038 2050 2053 2056 2059

I thought 2030 was bad but 2059!

Is this a bug or what, and any ideas on how to fix it other than running sed over all the files and replacing all years to 2024? And given what I know about spaced repetition, isn’t the furthest in the future date around a year ahead?

Any help or insight will be much appreciated