Floor tile is visible through wall at certain places

When placing floors underneath window tiles, the wall ajacent to the window on the right turns black. Even after demolishing it and rebuilding a new one, it turns black again straight away

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COLLECTED HARDWARE DATA
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Device
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Model: System Product Name (System manufacturer)

Operating system: Windows 10 (10.0.0) 64bit

RAM size: 32 GB

Battery status: Charging
Battery level: -1

Processor Device
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Type: Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz
Core count: 8
Frequency: 4 GHz

Grahpics Device
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Vendor: NVIDIA
Type: NVIDIA GeForce GTX 1080 Ti
Memory Size: 11 GB

Screen Summary
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Full Screen: True
Resolution: 3440 x 1440 @ 120Hz