Yes, it's theoretically possible that closer entities are clipped and further away entities are still visible. The reason is that an engine frustrum is a truncated cone, rather than a sphere segment. Still, this should be an extremely rare case and have no affect on real games.

I suggest that you measure the distance to the player and compare it with clip_far. If the distance is smaller, the player should be visible. Also check if the player is not set to the view.genius, or something like that. If you can't find a reason for the clipping, please sent your level, or preferably a stripped down version, to the support. I'll look into it.