My 4 triple purple desert roses have been blooming beautiful blooms for 3 years. This year all the blooms have turned to light pink and white. What would cause this? Please help

Maybe @GigiAdeniumPlumeria can help

@Kimbridgeman to NGA. Do you have a photo of before and after?

The majority of the grafted desert roses blooms are not stable. Winter early spring, their bloom could change dramatically but it will revert back to its normal color summer to end of the year. Here's an example of the color change:
Desert Biscuit:
1/04/2022


6/22/2022


9/27/2023:


11/07/2023:

4 separate plants changing colour the same way makes me wonder if there's something in the soil conditions. Are they fertilized the same way as before?

My seed grown triple that has been blooming for 3 years has had a lot of colour shifts as well ranging from predominantly white with pink patterns to solid hot pink and various versions in between.

In the case of @Kimbridgeman that could be a possibility, especially if this is the first time he has seen this change of color of his 4 desert roses. Hope he stops by again to let us know if that could be a possibility.

I'm guessing too it could be temperature related if all 4 purple exhibit the same shift in color. Like I would notice my two King Purple shift color at the same time:

3/26/2022:

4/20/2022:


9/25/2022:


In either case (fertilizer or temperature) the change in color is normally temporary and he could see all four bloom purple again once we start the late spring or summer.