I've had our 2018 at the dealership several times and I always get the "unable to duplicate issue" statement. I even mentioned I'd read it was a software issue but so far it's not been fixed. It's such a random occurrence it'd be nearly impossible to duplicate while at the dealership. Ours started at around 7000 miles and it's got a little over 20,000 on it now. It'll probably wait until right after warranty to finally quit completely.
If you can take a video of it happening they might be more willing to help. Also give them the TSB number if you haven’t already.