alan.schmitt@polytechnique.org writes:

[...]

> I need to schedule something for 2039, but when I do it the date is set
> for 2037. I tried with a plain emacs config and I see the same issue. Is
> this a bug?

Sounds like the bug of 2038¹. I assume that 32 bit integers are used
somewhere to encode the date.

For the record, I see the same behavior.