doing this:
permission.playerRemoveGroup((String)null, player, oldRank);
permission.playerAddGroup((String)null, player, rank);
works fine in PEX but switches out the ranks and playername in PermissionsBukkit so I get this:

repored in the comments of my plugin: http://dev.bukkit.org/server-mods/autorank/#comments

ok thank you, I'll update to the newest release :)

Yup, this was also reported by another person here #31.

This has been fixed in this build: http://ci.milkbowl.net/job/Vault/108/

Will eventually have a release on dev.bukkit too.

@Armarr - I'll be waiting till the RB comes out hopefully later today before pushing a new Vault.