From what I can tell, it does appear to be a bug. I have submitted a bug report to Adobe on it.
https://bugbase.adobe.com/index.cfm?event=bug&id=3596008
What seems to be occurring is that coldfusion.image.ImageReader is trying to find the CLibJPEGImageReader class from the collection returned by javax.imageio.ImageIO.getImageReadersByFormatName("jpeg"). This works fine if it is the first object returned in the collection, but if not, it will return another JPEG ImageReader that does not support CMYK images. I have two systems (both RedHat) which are currently in each state. One has the CLibJPEGImageReader as the first element in the ImageReader collection, and in the other, it is the second element in the collection. The code below will work fine when the correct reader is found, but not when it isn't the first element in the collection.