Yes, sometimes after a multiplayer ingame glitch that rarely randomly occurs for certain players, Toribash may load some player's items for your Tori or Uke (as well as Toriko or Ukeko), so they 'own' the items (just in your custom folder). Therefore, at least in the singleplayer mode you can see that ground texture that is considered as Tori's or Uke's one.
As zwouter said, clearing or redownloading their custom folders should help.
If it doesn't, better to check again if you did all the job with customs. And if it's alright but the problem stays, i see three possible ways:
- Deleting all the customs folder.
- Reinstalling the game.
- And if these steps seem too much a work for a single texture, just admit it and let that ground be.