CT5-V Blackwing surging or bucking

My 2022 CT5 Blackwing manual has a similar occasional issue since new. Happens only in the morning when the vehicle is cold, ususally within two miles of leaving home, rate of speed usually less than 45 MPH in fourth gear. When it does happen, it’s significant. Slowing the vehicle down or speeding up doesn’t help. It just seems to play itself out in about ten seconds. My Cadillac dealer has reviewed this issue many times, kept it overnight, tech has taken it home, etc. But since it’s occasional (as in it won’t do it while they have the vehicle) and the problem doesn’t leave any code for diagnosis, it remains a mystery.

I posted on this issue before. My ’22 Blackwing now has 14k miles and still gets that that infamous occasional studder, low RPM, 3rd or 4th gear, within 2 or 3 miles from home, first thing in the morning. My Caddy dealer has no idea of a cause. No codes. No GM tech reports. Nothing. Just annoying in an otherwise fantastic vehicle.