Problem/Bug permissionsEx Game Breaking Bug!

Hello, I recently switched from Groupmanager to PermissionsEx, And when i try to move people from one group to another with (/pex user {name} group set {group} {world}) it doesnt work half the time. Sometimes it will move them and then sometimes i have to retype the command 500x to get it to work and some times it doesnt work at all. I have done i little searching and it seems that others have had this problem aswell. But i have not seen any ways around this? Like a new update, patch, or anything.

Game Version = 1.8.3
Jar = Spigot
PermissionsEx Version = PermissionsEx V1.23.2

I think i posted this in the wrong place sorry u can mark it as done unless u have a fix :/

EDIT by Moderator: merged posts, please use the edit button instead of double posting.