Ascent to Power - Trial of Sekhemas not accessible

I can't access the trial and way point is not showing on the map although Boss is showing as killed,
It keeps displaying "Return to the Ardura Caravan and speak to Zarka"
But when I speak to Zarka nothing happens...

I had the same problem and I accidentally solved it.

Teleported to Act 2.

I went to speak to Zarka and then went to click on the map.

On the map you will see little blinking diamonds leading to different places.

I found a blinking diamond (SW of the map I guess) pointing to the Trial of Sekhemas.

And voilà!

I was there!

As additional info: it's the Desert Map on the Caravan, not on the World Map.