System Information
Operating system: Windows 10 Pro 10.0.16299 Build 16299
Graphics card: NVIDIA GeForce GTX 1070

Blender Version
Broken:
(example: 2.80, a205493426b blender2.8, 2018-12-03, as found on the splash screen)
Worked: (optional)

Short description of error
Camera keyframe malfunction

Exact steps for others to reproduce the error
I don't know if this is a bug or not, but I'm having all kinds of problems getting the camera keyframes to behave like they did in 2.79 or lower. When I set keyframes and then move the camera and try to set a new keyframe, the camera frequentlly pops back to the prior location and rotation.

I thought it had something to do with the check box next to the "lock/unlock" icon on the dope sheet that controls the F-curve, but unchecking it yields inconsistent results.

I cannot figure out how to make it work correctly all the time.

I feel like maybe I'm missing something that should be obvious.

I haven't been able to find an answer on any of the forums.
Based on the default startup or an attached .blend file (as simple as possible).