[ReFLeX135]

I originally heard this after driving around 25-35 mph roads, but after parking it was still occurring. Does anyone have any ideas on what this might be and how serious it is? I'm not currently driving the vehicle really at all since I'm working from home, but I do want to get it fixed soon and my dealer loves to turn people away if it's not replicated on site.

Info:
2017 Camaro 1SS Auto NPP with around 48k miles. TC was flushed a few times last year for the TC issue.