Because of an error in one of the tools to make custom objects, some of them are faulty causing the Blue Lot Issue.
Blue lots have been getting scarcer but I do think that those items can crash your game now. Originally only package files were affected by this problem but some people thought it would be great idea to just convert them into Sims3Packs, assuming that would solve the problem. Well, it didn’t. What it did do is that now some of this files are floating around as Sims3Packs. Most of the original faulty package files are long since repaired but now the faulty ones can be found in the Exchange.
Identification in Custard
Custard does show them as faulty. They show as Corrupt (TXTC).
Do not install those downloads and do not re-upload. They can only be found in houses (cause they are always objects). If you absolutely want to use the house, remove the Download with Custard before installing the Sims3Pack.
I’m unsure if the FIX option in Custard can actually fix those downloads or not. Dashboard can fix the package files so it might be worth a try.