2003 Yukon XL rolls forward and back about 5" when starting

My 2003 Yukon XL will sometimes roll forward about 5" and then back when I start it. It is always in park when started and this issue is intermittent. Any suggestions will be appreciated!

The only thing I can think of that could cause this is, if the Torque Converter Clutch is somehow engaged when the engine is started. This then causes the vehicle to roll forward that 5" until the TCC releases.

When was the last time the transmission fluid/filter was serviced?

Tester

Do you normally use the PARKING brake or not?