Jacketed Bundled Cable = JBC
Regular Bundled Cable = RBC
Possible to place JBC above RBC when placing on RBC, but this is not possible when placing on the JBC.

I have no idea what you are talking about.. :)
Please elaborate.

Bug confirmed if I'm interpreting you correctly
XJ
B
(This is a view from the side)
B = Bundeled Cable
J = Jackated Bundeled Cable
You can place X (a Jackated Bundeled Cable) on B, but not on J

z15 has interpreted me correctly. Sorry for the bad description, wasn't exactly sure how to describe it.

Yes, its placing on a bundled cable is registering as not valid unless that block is completely empty.
Im looking into it.

Fixed via 1274f7a