Good day, I hope you are all doing well.
I have tested for the bug on multiple versions.
From version v0.19318 to v0.19320 build 20150711_191815, the bug occurs. These are all fresh installs.
How to recreate the bug:
After a fresh install, start a new world. Get some logic blocks (I used one "Button" block and 5 "AND-Signal" Logic blocks) and hull (to make a surface to place on).
Make a surface to build on, then place one "Button" block. Then next to the "Button", place 5 "AND-Signal" vertically. Select one of the "AND-Signal" blocks and connect it to the "Button" block; repeat this for all the other "AND-Signal" blocks. Copy the setup and paste it anywhere. The copy should now only have one "AND-Signal" block connected to the "Button" block. All the other connections in the copy are gone.
This occurs with the other signal blocks as well. (Other signal blocks were only tested in v0.19320 build 20150711_191815)
Here is a link to an image that show the result: http://i.imgur.com/W67xjOS.png (left is the original, right is the copy)