Oddly colored noteheads (Not in another voice)

I have some notes that have mysteriously changed color to olive green. I did not change them manually, they are not in the second or third of fourth voice, and using the color option while the noteheads are highlighted and changing them to black doesn't fix the issue. In the accompanying image, you can see the two runs of notes that are NOT black and which WON'T allow modification. The reason there are two sections is because of having copied and pasted the notes (although I modified some after the paste). Even deleting and replacing them manually did not change the color back to normal. Any thoughts? :)