When a map is complicated or really large, sometimes static meshes, BSP, even player models, ammo/weapon pickups and projectiles don't have any textures. Instead, they look like this:
(BR-Slaughterhouse while I was running some benchmarking)
Nothing showed up when I used the Search button.
[EDIT] Forgot to mention that it happens not just in benchmarking but in actual play, too. Happened in CTF-DC-ParallelWorlds and the Coret remake that uses a lot of cutom meshes.