For a couple of weeks I'm now having the problem that objects (or npcs for that matter) suddenly pop out of nowhere although they aren't very far away from my character. Also do ojects and buildings often have bad looking texture like they are still using the distant view texture although I'm quite close to them.

This never happened before (of course there were sometimes (rarely) npcs popping out of nowhere, I think that's normal), but not to this extreme extent like the last couple of weeks.

I didn't change any settings or add any mods. Is there a way to prevent this?

What are your specs?

Have you verified the cache through Steam ? There may be some corrupted or missing texture files.

Also check the 'distance' settings from the launch menu. There's one covering npcs - increasing the setting might solve the 'popping' issue.