Sphinx of the Second Sun second beginning phase glitched

This card properly gives the second beginning phase but you don't get your post combat phase when this happens. You should be able to cast spells or activate abilities but instead it goes straight to end phase after your second upkeep.

Start by reproducing the Sphinx of the Second Sun scenario and tracing the turn phases after its second upkeep. Confirm that the post-combat main phase occurs and permits casting spells or activating abilities before the end phase.

Written by the indexing model from the issue text.