Keyframe Caddy is a crude piece of software, but I doubt that it could be responsible for the behaviour, described by the OP.
With Animate having native Frame Picker, I can't imagine why anyone would use the Caddy which was popular years and years ago, but the picker should perform much better, covering all Caddy functionality.
I'm at a loss what may be the reason for the offsets, but it could be bugs related to Layer Parenting if things are parented, display scaling, camera bugs or something along the lines which messes up the coordinates. The latest versions of AnCC are full of hidden surprises.
It could as well be user error, if he's moved the content inside symbols.