Dealership test drove 2019 for Transmission Slipping, says couldn't replicate the issue, sent me home no charge

2019 94,000 miles. I know there's plenty of talk that people are annoyed there is no trans recall. I've felt something off for a while and the other day it was pretty bad. I have 60k left on my extended warranty and feel decent about that. I hopefully still have a few years left before I hit that mark. I put 20k miles on it pretty quickly in a year and a half but now do not drive it very often. When it did it the other day it was every gear struggling. They didn't see anything alarming when they test drove it. But at least it's on record that I noticed it. I'm hoping if it does go, that they'll honor the warranty and I'll be good. My best guess is they're ignoring it until it actually breaks? I asked about the known issue and they were very nice and accommodating but I could tell her was not being truthful when he said it's a lot of misinformation about it being a known issue.