I have questions… I haven’t seen this before so may not be able to help but I am curious …
Is this a group game by any chance?
Does your pumpkin have the same texture as the wood meshes? Because it changes from orange to green as well.
And what are the properties of the meshes? - reflectance and such
Do you have any scripted properties or functions for these meshes? ie Are they supposed to change when something touches them?
Most likely the textures are not loading for some reason. While playing the published game, hit ctrl+F9 to bring up the dev console, then select Log->Server. See if there are any errors showing up that can help troubleshoot.
This could be happening from either a glitch, bad internet, studio is not loading properly, the game is slow to load, or because a player is messing with it.
Here are some more reasons
Maybe your game is just messing up or since they are the same texture you probably had it touching grass & changed the colors to green like your grass.
Did you have any it at a different color at first?
Did you publish the game as that excact color?
Do you happen to have any other players helping you with this project? When excactly did this happen?
You should try tapping them as the colors at a time.
Maybe also you could try making the grass a certain color like a different shade of green and trying again saving the game.
Did you make sure that you selected the whole creation? Maybe you left out the lighting piece? You could’ve accidentally deleted it or it just doesn’t work in Roblox Studio.