When you break a advanced drawbridge with a pick you double the drawbridge.
the normal drawbridge doesn't have this issue but the other 2 do.
If you destroy it with a pick it doubles the drop

1.6.4-Forge9.11.1.965
TConstruct_mc1.6.4_1.5.3d3
TMechworks_mc1.6.4_0.1.3

I also got this, however after placing down the drawbridge that was duplicated, (with items already in the advanced drawbridge inventory) and activating with a rednet cable (not sure if the method of activation matters, will test further) the server crashes.

crash log: http://pastebin.com/Y8V7YMQ7

@teutates1989 What modpack is it?

And maybe exactly what you put on that pick (including materials it is made out of)

@sebi2306 Its a custom modpack. i have this problem in both of the custom modpacks.

Its with every pickaxe (vanilla, tinkers construct)

I was having the issue in direwolf20 1.6.4 pack with vanilla iron pick
On Mar 9, 2014 3:30 PM, "teutates1989" [email protected] wrote:

@sebi2306 https://github.com/sebi2306 Its a custom modpack. i have this
problem in both of the custom modpacks.

Its with every pickaxe (vanilla, tinkers construct)

Reply to this email directly or view it on GitHubhttps://github.com//issues/20#issuecomment-37136189
.

@jgdovin which version of direwolf20 1.6.4?

This works with Direwolf20 1.0.19, Tested and screenshotted.

Fixed.