Season/Mission Reset?

https://preview.redd.it/sknvn1at5kxd1.png?width=543&format=png&auto=webp&s=ea82beba81e24910702e5ce4d30e430c673ffb2a

Can anyone clarify what the two different dates are for? I'm presuming one is for the mission tree and one is for the season? I can't work it out! thanks in advance