There seems to be a problem placing landfill under lights.
This blueprint doesn't get landfill placed properly:
0eNqV1N1qgzAUB/BXKec6KX5VW59gF7vzYhdjjNge3IEYQxLLSvHdl9gxZFTUG/VI/j9NDskdatmjNqQclHewSmjuOt4YuoT6G8o0YXALt4GBqG0ne4c8jNOkGiid6ZEBnTtloXz3AjVKyJB1N41QAjlsgYESbaiMIAleInVBj8cDW4zU1HCUeHaGzlx3Eif55Gn+Ssb1/s0f8RjBq0kyXfFl2wopuRStngSz4YMBKkeO8DHlsbh9qr6t0fg5Pcsz0J31kU79LiuP94dxYcPDEH7mH5OsYpaUdJ2SLTDZOqZYYA6rmDRaYPJ1TLrAFNsaNaMcN/VpBjlta9OMEkfb2jTHxNvaNMck29o0Mn5vjXuwnJxLDKSo0W9TeHmrdpXzZ0jz5Xav4Wp312Qf+SFXNHZEk2OcFdmpyIs4yg/5MPwAhWuSXA==
Resulted in this for me after landfilling:
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

Is this easy to fix?
I haven't worked on mods other than to use them, but I am a software guy so could probably fix this given the mod source. Is it available somewhere? I didn't look yet - but it may just be in the mod itself.