At least two 3D-background buildings in the First City keep vanishing an re-appearing:



I also wanna add that the signs in the First City switch from Klingon to English wayyy too early - at a distance where it is barely visible.

Perhaps the Klingons are experimenting with small-scale versions of ground emplacement cloak generators.

Most likely... still it's very annoying seeing these buildings flickering all the time. It's probably connected to the general and looooong-standing issue with the flickering background nebulas in space...