I have Tmax developer that I bought 18 months ago and mixed 1 liter back then. The remainder of the concentrate was stored in a cabinet. The other day, I mixed another liter from concentrate. The diluted Tmax developer solution is the color of Coca Cola (before developing any film). I don't develop film very often and I don't recall if this is something normal for newly mixed dev. Does the darker color indicate anything abnormal?
