The HD Pack on Steam has outdated models with some animations missing, which are known to cause some problems in mods. There was an official patch for Blue Shift released (184.108.40.206 - 8/14/2001) to fix this, the following files should be updated with the models from that patch:
There is a way to add these files manually: http://steamcommunity.com/app/70/discussions/0/864958451481132971/ But this is not the right way.
I've got the bshift hd model pack brewing for the bshift release, I'll look at moving those models over.
Looking forward to BS and OF as I haven't played them yet. :)