Sphinx of Second Sun triggering at the end of the second main phase instead of beginning

[scarlet nova]

As the title says, Sphinx of the Second Sun enables the trigger for the card's ability at the start of the post-combat main phase, however the effects happen at the end of the post-combat main phase. Pictures included shows the trigger, and no resolution with untap, upkeep, or draw happening.

[stiff plume]

This is how the card works. [[Sphinx of the second sun]]

[tropic bronze]

https://scryfall.com/card/mkc/118/sphinx-of-the-second-sun

Sphinx of the Second Sun <:mana6:292901508780130304><:manau:292901508754702338><:manau:292901508754702338>

Creature — Sphinx
Flying
At the beginning of each of your postcombat main phases, there is an additional beginning phase after this phase. (The beginning phase includes the untap, upkeep, and draw steps.)
He watches in silence as the shadows shift, bringing Amonkhet ever nearer to the Hour of Revelation.
6/6

[stiff plume]

"there is an additional beginning phase AFTER this phase"

It's a common misread of the card, almost everyone mistakes it