Describe the Issue: One can invite both +5 lvl and -5 lvl in group at one time.

How to reproduce: Invite all player which you need while each of them +5 lvl AND -5 lvl before any of them will accept invitation. For example at lvl 25 you can send invite to lvl 20 and before he will accept - invite also lvl 30. 

Character the bug occurred on: None at my char, but get instruction in discord from one guild.