Sometimes when I go to my machines, I have to re-place them again to allow them to connect to cables. Cables might do the same but I haven't got the issue to happen again yet.

The cables were placed after the chunk was loaded again. The machine on the right was re-placed to get it to connect again.

This is IC2 1.1.3.3 on latest Forge with KCauldron.

Happened again, here's a video:

http://nentify.me/2015-12-15_13-18-03.mp4

Here are the chunk boundaries - Some machines/cables in the same chunk don't connect and the cables are vertical.