Zahua Secret of Tacan waterfall bug: no interaction

[Eus]

Anyone else also experiences my problem with Zahua's Secret of Tacan quest where after talking to the haggard man who asks for water from the waterfall, the waterfall can be highlighted in blue after holding the A button and using the L analog stick to point right, but no symbol to start the scripted interaction appears on the waterfall (and hence nothing happens when the A button is released while the waterfall remains highlighted in blue)?

https://gamefaqs.gamespot.com/a/faqs/97/79897-1081.jpg shows both the waterfall being highlighted and the question mark symbol to start the scripted interaction. The problem is that the question mark does not appear for me.

I experience the problem in Nintendo Switch.  My Pillars of Eternity version is 2.60.0, and my Switch firmware is 19.0.0. I have restarted the Switch but still cannot resolve the problem. I also have opened all of the map without Zahua to complete other quests first (e.g., bleak oath, the missing girl Myla, and terror of the White Hollow), but the problem remains. My party members are me, Aloth, Durance, Maneha, Grieving Mother, and Zahua. Another significant problem that also occurs at the same time is that I cannot see Odeyna Fyrgest anywhere in Caed Nua despite the distinguished visitor being reported in the stronghold management screen and by the keeper statue in the hall.