[Several graphical effects are pink squares after 3.07]

Yes, definitely not only Steam, but also GoG.

 

In addition, there is a game-breaking bug regarding White March content (NPCs not doing anything):

https://forums.obsid...vents-response/

[PoE 3.07 WM no NPC/gameplay events response]

I am experiencing the same issue.

 

And it looks as if the exact same issue happened in the past as described in this thread:

https://forums.obsidian.net/topic/81825-everythings-gone-pink/

[Everythings gone pink!]

Has anybody found a solution for this?

 

I am on macOS 10.13.1 and experiencing the exact same issue with the most recent version from GoG (3.7.0.1284). Cräghold Bluffs shows pink artefacts like the first poster describes and the mercenaries do nothing. Going to stalwart village, the screen goes mostly pink and the map looks exactly like the first poster describes.

 

I already tried deleting the game and re-downloading from GoG (through GoG Galaxy) to no avail.

 

Addendum:

As a last resort I tried the manual installers available at GoG - unfortunately these make no difference. The game is essentially unplayable in this state *sad*