4l80e issue

[B2usmc]

I have a 99 Sierra with a 5.3. 228r cam and supporting Texas speed springs, ported heads, etc. 4.10 rear end. Also has a 4l80e with adapter harness, a shift kit and 3500 stall TCI converter. My issue:

First vehicle with a high stall converter
Runs and shifts fine from cold start. Sometimes it doesn't seem to hit OD or maybe 2200 rpm is normal for the rear end/trans combo.

When I turn the truck off and restart a few minutes later (warm start) I have to rev it to 3500+ to get it into a gear...also the gear selector switches back and forth while this is happening until the rev makes it "catch", then it drives fine and selector shows either D or R, whatever was selected.

I know this isn't normal, but what are my options to fix it? I've had numerous performance cars, but all had manual trans, so I'm a little lost with the automatic. Im reading and learning the concepts, but this issue doesn't seem like it's been addressed.

Any help is much appreciated,

Bryan
Marietta, Ga