Physics engine only update my arse...
Ghostly is now only giving a 10% concealment miss chance vs the 20% it was originally.
We noticed it last night as we were running Cove and as much as possible tried to confirm the change on lvl 16 and 20 Mabar Cloaks and lvl 16 and 20 Manslayer Ring (funny how nerfs can still affect all previously created gear but upgrades do not without effort and resources on the player's part). This does NOT appear to be a bug as the actual text of the effect has been changed as well.
I haven't seen anything about this in the release or patch notes or reported in any other posts so I figured I would throw it out there in case anyone else missed it.