Hullo, another Model 3 driver here. I mentioned this in another comment, but it's relevant here; OP wasn't using Autosteer or Autopilot, they were using cruise

Hullo, another Model 3 driver here. I mentioned this in another comment, but it's relevant here; OP wasn't using Autosteer or Autopilot, they were using cruise control: a miles more simple system--and that system behaved in a way that seriously reduced confidence in it. (For the record, I've experienced exactly the same behavior in my M3 as well.) So, if we can't trust something as simple as cruise control, and we've seen similar confidence-eroding issues in the autopilot features Tesla has already deemed "good enough" for a live release, I think it is 100% reasonable to be skeptical that Tesla is anywhere close to "solving self-driving." They have a history of overblown claims and faulty software in this realm--as much as I adore my car and the disruption Tesla has done to the industry, Tesla does not deserve the benefit of the doubt in this realm, especially not with safety-critical systems.