Mocha Pro 6.0.1 OFX plug-in in Nuke 11.2v3. CentOS 7.2 on HP Z840 with NVIDIA P6000
Deleting a keyframe and hitting undo restores a keyframe but not the one you had before.
Make a shape on frame 1.
Go to frame 10 and change your shape so it creates a 2nd keyframe.
Go to frame 5 and move the shape somewhere that’s an obvious change. so you now have a 3rd keyframe.
Delete this newest keyframe and the shape will go back to where it was.
Hit undo. The shape will not move but a new keyframe will be created.