short rider auto flowering strain

I have just germinated 5 short riders. Now at 1.5 inches the cotyledon leaves are bright yellow/orange in colour. Has anyone seen this happen before. Is it normal for this strain? All 5 are exactly the same. They are in small grodan cubes in a heated propogater.

The cotyledon leaves usually turn yellow and die when the plant gets a week or two old....

yes but these are yellow from hatching. They threw of the shell and were yellow when they opened. Do they need light yet?