After completing Glenwald and seeing the story complete the game crashed before seeing my Tainted Essence screen, and upon reloading I have not unlocked the 4th Haven despite earning the achievement for doing so. I didn't take screenshots of the graphical errors unfortunately, but they may have been caused by attempting to drag the map as the enemy phase began.
There were graphical issues prior to the crash on the final turn; my panic bar and the settings menu background disappeared (although the line indicating panic and text in menu were still visible), and during the story outro the animation showing the beam of light was missing (text was there, no images above it). Dialogue between characters still played as normal
I have earned the Tainted essence from the final night (~20,000), but did not earn a favour/Blessing for completing the location.
[Update] Now having an issue with accepting the favour to unlock the 4th town, doesn't appear until spending essence and doing so locks me into the omentatum "until I visit both sides" but it never disappears.