Banned for wallhacking tomorrow!

That looks like the texture indicating where RA spawns which is layed upon the ground floor texture. This is probably only a problem due to your cfg.

http://imgur.com/C78FGai

I've take a screenshot from Radiant to show you what it looks like in the editor, it seems your cfg has problems showing the correct layer.

http://pastebin.com/693W5iR1

here is my config.
obviously it doesn't flicker if i set picmip to 0/1, but it shouldn't be the setting that causes it cause I imagine lots of player have higher setting on their picmip.

It's not the config, the texture/shader of the item decal is missing.
I suggest to reinstall the game.

Edit: Also remove any custom pk3.

pk3s as in custom maps? I have some defrag maps, could they cause it?

Yes, they could potentially be causing it.

yeah, it was resolved when I deleted all my pk3s. Thanks!

change your picmip

It's known as zfighting, they usually look at fixing these issues when found, but if cityy can't replicate it (comment 4) then it's not the map, follow his advice.

It's funny how odd the topic sounds out of context.