Operating system: Win 10
Graphics card: Nvidia GTX 1070
Broken: 2.80, c13e10a7404d, Branch:blender2.7 , 2019-06-04 00:52, as found on the splash screen
Short description of error
When baking animation to new action (from NLA editor) custom properties on bones will not be keyed and baked down.
Exact steps for others to reproduce the error
Create 2 bones with one bone having a custom property on in the bone tab. Drive another bones position or rotation with that custom property. Set keys and change the value of the custom property over time. Create an NLA track from the current action. Select all bones in the armature and bake using the "pose" setting and "selected bones" options. Observe that in the new action, only translation, rotation and scale will be keyed, leaving the custom property unkeyed. When muting the original NLA track, the driven animation will no longer play.