According to the parameter dials, when the prop is loaded and not visible, where is it, in terms of X, Y and Z ttranslation?

If you select the top camera, move it out to 1000 per cent, or similar, and then increase the size of the loaded prop by something fairly drastic, can you see the prop then?

If it's a small prop and it appears centred and if there is already something there, the prop won't be visible until it is moved, but that, of course, was true before SR2, as well.   I applied SR2 a while back and I haven't noticed a problem with vanishing props.   I have imported the odd obj since then, although probably nothing in 3DS format.