I released WWMT 1.861 today with fixes to the SMD exporter. These fixes relate to the exporting of models with a Skin modifier. It also fixes problems with models using the bodygroup functions.
Hopefully, this now fixes all the features that were broken since WWMT 1.856 which changed the SMD exporter to accomodate CS:GO, SFM and possibly other mods that no longer export $origin like previous versions.