Hello, my players can place heads in PS cuboids

Could you post the field from your config that they are able to place the heads in? Posting the permissions related to PreciousStones that those players have would be helpful as well.

config - removed 2015-11-20

Players permssions:

preciousstones.benefit.info
preciousstones.benefit.create.forcefield
preciousstones.benefit.create.unbreakable
preciousstones.benefit.setname
preciousstones.benefit.visualize
preciousstones.benefit.mark
preciousstones.benefit.who
preciousstones.benefit.onoff
preciousstones.benefit.counts
preciousstones.benefit.locations
preciousstones.whitelist.allow
preciousstones.whitelist.allowed
preciousstones.whitelist.allowall
preciousstones.whitelist.remove
preciousstones.whitelist.removeall
preciousstones.bypass.limits
preciousstones.admin.info
preciousstones.limit3

I've tried the field design you linked to but was not able to replicate this issue (While using build '#528'/v10.0). Perhaps this is caused by a conflict with another plugin?

I update server to spigot 1.8.8 and preciousstones to latest build, still nothing. They are heads with skins.

Sorry for english