I mix the developer in the light, and the shift is always the same, yellow, then a sort of a gray green, but then to that pale "orange". Has always done this, even with a new bottles.
It will be interesting to see what happens when i run some other tests. i will let you know. Hopefully, that will be in the next few days. However, my students come first and as they are right in the middle of a film/developer class it is hard for me to develop negatives when they are doing theirs. So it might be the week end before I can develop my test rolls.