Sure, you could have missed a lot like green numbers in his cycle. As I said before, I suspect you are missing Frankie going green. You could do what was done before and go ahead and drop dose to 1.25u and see if the pink goes away. If it were me I'd wait until the weekend, if that is when you can get some tests in, and see if he is going green. You'd have to pick a day that doesn't look like a bounce day.
I hear about "this didn't happen with PZI" every know and then and each time I think, I'd like to see those PZI numbers -- are they around anywhere?