Warning : spoiler ahead.

In the desert temple, once I had reactivated the altar, I went back in, and immediately spent 10 divine seeds to repair the temple before meeting Damia there... Which prevents me from finishing the "To the Desert Sands..." quest.

And obviously I overwrote the save file right after I repaired the temple so I can't revert.

Using an RPGM save editor online I guess I could "unrepair" the temple or mark the quest as completed, right ? What should I modify in my save file for that ?

Further information on softlocking : At some points in the game, you can access several main story quests at the same time. But if you do not follow them in order, for instance, going to the Bee Queen before the Dryad temple, you can finish the quests, but they do not appear in the journal, and are never marked as completed, keeping the story from going on.