GvardianDLVII

Anyway, I found a workaround that doesn't require any rollback or console tricks - you need to use those "shrines" (marked in red) to fill both blue areas with water, then a spirit in violet rectangle should appear. Being more detailed, you need to first use the top shrine to fill the topmost sink (then there will be a strange situation where both the middle and the lower sinks are empty), then you need to use that bottom shrine to fill the middle sink (most likely you will need to click the shrine twice, as the first usage will fill the bottom sink, leaving the middle one dry). Then you need to enter the Drowned Crown area and using the portal on the right in there, leave and re-enter the entire Drowned Kingdom area - you will then spot a spirit waiting for you.

Wow, it must be a very hard bug if it takes the dev team more than 2 years to fix it and they still didn't make it... I just came across this issue, 4th soul is not spawning, and I'm stuck. The last save would require me to rollback almost entire DLC (I've already completed the trial and the bridge areas), so it is not an option for me. I'm afraid using console will break achievements etc.