CS 1.4.6 Terrain shadows breaking in Markarth

[SkrubbySkrubInAShrub]

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This is an issue I have been seeing since at least CS 1.3.6. Terrain Shadows are not filtered and seem to be using the wrong heightmap in the Markarth worldspace. I am not sure if this happens in Markarth only or also in other places, however I have observed that this issue is inconsistent. Normally in markarth no Terrain shadows are applied, and the debug menu shows the most recent active heightmap from the previous worldspace. Sometimes however it does start using the heightmap and the data is being updated in markarth, leading to broken shadows. https://streamable.com/sjmnq2

How it would normally look like (Note how the heightmap in use is from a different worldspace, the data is also not being updated): https://media.discordapp.net/attachments/1082470370902294600/1430685570035613707/image.png?ex=68faad44&is=68f95bc4&hm=4a4ca68cbcefacd403c967a31dac016564d6373b9e775063b1d92e65a07a1e2f&=&format=webp&quality=lossless&width=1232&height=693