If it's in the same spot as before - and there have been no other significant changes to its condition or situation - then it's the weather.

I live in CT. My dissectums just started turning color. Give it some time.

Thanks...guess I'll give it some time.

Bboy....now that you mention it...it does so happen I moved to a new apartment and where the balcony gets less sun. Before I was in DIRECT sun all day. Now it's more of indirect LIGHT all day..but not direct sun. That was on July 25 that I moved. I wonder if that could be the cause? Does less direct sun over the year affect the degree to which a maple turns color in the Fall?

Yes, it does.
Our native Vine Maples have much more color in the sun than in the shade. Also, I grow several hundred Japanese maples in the ground and in pots and am able to observe it first hand.
Mike

btw...just a few days after my last post here, indeed, my maple began to turn color, and is now a glorious golden yellow/orange! ;-)