For the purpose of this bug report, I've attached a 10-slice sample stack. However, this makes replicating the problem harder - using the Make Substack command seems to save the color information into the sample stack attached (forcing subsequent openings of this file as a colored stack).

In my original 361 slice stack (178MB, too large to attach) opening with SCIFIO disabled allows the image to be read in grayscale. Turning on SCIFIO causes it to apply a pseudo-color code to the first 6 slices (as seen in the sample stack).