Reported by @brishtibheja in https://forums.ankiweb.net/t/my-cards-intervals-dont-seem-to-be-going-up-when-correct-and-some-go-down/58337/2?u=anon_0000

Q: My interval went down (e.g. from 4 to 3 days) after optimizing my FSRS parameters. Why is that?
A: If you optimize your parameters, FSRS might determine that the intervalls should be shorter than it previously predicted. The reason is that the DSR values are recalculated, if you optimize your parameters.

I'll be adding a PR in a few days.