Entering the Galai Gates through the waypoint gave different instance than I'd left via town portal

I had partially completed the Galai Gates when I went to complete a trade. Took a town portal back to the Khari Bazaar, waypoint to the Ziggurat Encampment, completed the trade, and then waypoint from there back to the Galai Gates. When I arrived in Galai Gates the map had reset, even though I had only been away for a few minutes.

I used the waypoint to go back to the Khari Bazaar and entered my town portal and was then back in the instance I'd left before the trade.

I play on xbox series X.