Animation > Flatten All Motion with Constraint fills the timeline with erroneous keys up to the largest keyframe previously occupied by animation data in a project. It does not start out in this state, but rather, it takes a series of actions to produce this state and once it occurs it remains for the life of the project.

STR:
- create a new iClone 8 project with a non-standard humanoid character
- add a 500 frame animation to frame 1 of the timeline
- select Animation > Flatten All Motion with Constraint
- note that the 500 frame clip is flattened and no additional keys are appended past frame 500
- place the timeline cursor on frame 500
- add the same clip again so it is appended starting at frame 500
- select Animation > Flatten All Motion with Constraint
- note that the two clips is flattened and no additional keys are appended past frame 1,000
- place the timeline cursor on frame 700
- click the Break button in the timeline toolbar to split the clips at frame 700
- delete the second 300 frame clip
- select Animation > Flatten All Motion with Constraint

Expected Result: The animation will be flattened and no additional keys will be appended beyond frame 700

Actual Result: The animation is flattened and a copy of the last frame will be duplicated across frame 700 to 1,000