Warning light on 2006 Taurus

I have a 2006 Taurus se with a 3.0 V6 and Auto trans. Lately when i drive it for a distance under hot conditions, especially with the AC running, I get a "Check Transmission" message on my dash. After the car cools, the light goes out and the car seems to shift better. This problem started a short time after I had the Tranny flushed. Could this be the problem?

1) Check the transmission fluid with the engine Idle, and at normal operating temp.
2) Log all DTC's and other symptoms.

Fluid is slightly over full and a perfect color. The only other symptom that I forgot to post is when I take off too quickly the tranny will feel like it is slipping. Once I let off the gas it will shift into second and run okay.

How many miles are on her?
Was it a flush, or oil/filter change?

Just a flush. fluid looked good and did not smell burnt, but had no idea how long it had been since it was done.

Mileage is about 130,000

Mountains, Heat, and a new Transmission flush!
1) Turn HVAC on cool high max, and make sure both coolant fans are working.
2) Make sure in front of transmission cooler, air condition condenser, and radiator are free
of road litter, and bugs.
3) Monitor + Put some miles on.

How many miles are on her sense the flush?