There is a crash when placing a mech.
Here is the crash log: http://paste2.org/f1atfb1g
Here's the errors given in the server log: http://paste2.org/dAmZzCYP

This is occurring with the latest compile of the dev branch.

What happens is that a player places the proto titan which causes the first "silent error", the proto titan is invisible.
When a player attempts to get into the titan, the second error occurs and when a player attempts to break the titan, this error occurs: http://paste2.org/zcGZD2kz

Single player is not affected by this crash.

It would seem that this crash only occurs when using mechs that are spawned using commands such as /give.
Creative gamemode spawned mechs do not cause the crash.

Crash also occurs when a spawned plane is renamed in an anvil and then placed. I guess NBT data is just really messed up for items spawned with /give commands.