What do you think of the mystery of the switched Headstones?

Last month when I went to the cemetery to visit my grandparents graves, I found a startling revelation! After 25 years Grandmothers headstone had been changed! Grandmothers headstone had been gray granite for 25 years and had matched grandfathers for all those years...but now it was PINK! The name was the same, the dates were right, but the color is PINK and it sits up now not flat like it was and not like Grandfathers any more...how did it just change I wanted to know. So after cleaning up around the graves and still wondering what is going on here I went up to the cemetery office to see what they knew. Of course they knew nothing, nothing at all tried to tell me the 25 year old headstone was still out there, yea right I'm color blind? After leaving the cemetery I starting calling family members trying to find who changed the headstone, no one would say! What am I to think? The headstone just turned PINK by its self? Not only that but it sits up now and not flat? I know a family member did this why won't someone speak up? Have I once said I was mad? No I haven't! Just would like to know is that too much to ask?