The best workaround for the lot-originating save problem is to test builds in not your regular save before putting them in your regular save. And on top of that keep a backup of your Saves folder.
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Comments
https://answers.ea.com/t5/Bug-Reports/NEEDS-SAVES-Orange-Exclamation-signs-over-lots-Houses-disappear/td-p/10533991
Thank you @mightysprite
Good idea @luthienrising I will make sure I do that