Hello Henri,
I cannot reproduce this issue and I unfortunately do not have any logs. Therefore I am putting this in the General discussion for a heads up. However, others have also notice that when logging in to a sim (currently on OS snail 0.9.1.0), not everything loads. I have a skybox I always login to. The Skybox was gone along with many other objects that I knew was still there when I logged in. I was just sanding on an invisible platform it seems. A relog fixed the issue however. This has happen a couple of times since the release of the current viewer (v1.26.24.0). But I am not ruling out this could be related to snail. This also happen when I TP'ed to another sim that was also on snail and the main building (prim made not mesh) was gone. Relogging fixed the issue. Might have been corrupted cache files which I did clear them after this occurred.
Also, which might be related or could be something else. Loading/rezzing of nearby objects is slow. When going to a new area on the same sim or on another sim, the objects are slow to rez. Also, when turning around the objects that was loaded has to load again. It's a little frustrated.
Just something to chew on until I can provide the logs.
Thanks,
Geoff