Sculpt objects going invisible

[Fennet]

And yet another glitch: Can anyone explain to me why various sculpt object have an annoying tendency to go invisible on me? I have no idea whether or not other people can see them, but my searchbert can, and does, find them. Until today they always re-materialize as soon as I restart the sim, but now I have one that seems more reluctant to re-appear. I can neither see it nor delete it, and it's driving me mad. 

Is there anything I can do about it? Please, let me know.

[Jasmin Helstein]

If this is happening to me I clear my cache, it always helps.