Forge Multipart - missing a mapping & not saving

[Wannabeuk]

Been having this issue since unleashed released, hoping the 1.1.3 would fix it, however it hasn't.

We are still getting an error when placing any microblock:

[ForgeModLoader] A TileEntity type TileMultipart_cmp$$3 at Wraith FTB Unleashed Server,-1261,69,-477 has throw an exception trying to write state. It will not persist. Report this to the mod author
java.lang.RuntimeException: class TileMultipart_cmp$$3 is missing a mapping! This is a bug!

We have standard 1.1.3 Unleashed with dartcraft disabled and hats and hat stand enabled, no additional mods.
Anyone know if there is a way to fix this?

 

[Ashzification]

From what you provided: " Report this to the mod author"
They might already have a fix for it.