Transmission Wierdness

My '02 Caravan with 4-speed automatic has begun to exhibit a problem that was dealt with, once, about 20,000 miles ago. I'd like to hear about anyone else's experience with this:
1. Sometimes, while trying to get under way at the first startup of the day, I experience a "no drive" condition. Placing the gear selector in forward or reverse has the same effect as leaving the selector in neutral. No torque is transmitted. Placing the selector back in park and waiting briefly before trying again usually results in the trans going into gear and operating as expected on the next attempt.
2. Decelerating from ~40 MPH or so, service brake applied, the downshift from fourth to third at about 30 MPH is very harsh. Only this one downshift is unusual. All other shifts, up or down, are normal.
The fluid is clean, and the level is correct (checked at operating temperature). Fluid and filter were changed once at about 20,000 miles (BEFORE this same problem developed the first time). The car has now done about 45,000 miles.
The remedy when this happened before, was for the dealer to re-program the transmission control module. I have an appointment for them to diagnose and correct the problem in a few days. Is this a recurring thing for anyone else? Is there a known problem with the transmission or the control module?
I'd appreciate hearing from anyone who can shed light on this.

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