I am using EssentialsX and most of the player and staff member use the /list command frequently. Unfortunatly the list-command displays the parent group instead of the primary group quite often. I have serveral primary groups listed in the essentials config and also several parents, but I have only issues with one parent called „Spender“. The only difference between the parents is that the parent „Spender“ has a suffix in the chat displayed with ChatControl. The real reason why I cant figure out the issue is that the problem appears often but not always. It seems like the plugin can´t find the primary group after an server restart anymore. So in order to clarify the statement: Using /list I want the player to be displayed with their primary group but never with their parent. I use „/lp user xy parent add Spender“ in order to assign a new parent to a player.
I appreciate any help you can provide 😊

LP-info of a player who has the parent „Spender“ and is displayed correctly: https://imgur.com/a/qeXLQ
LP-info of a player who has the parent „Spender“ and isn´t displayed correctly: https://imgur.com/a/Xtq4I

Vault: v1.6.1
LuckPerms: v4.1.25
1.12.2 PaperSpigiot: 1349
EssentialsX: 2.01.-bSNAPSHOT
ChatControl: 7.8.1

Vault-info:

 [Server thread/INFO]: [Vault] Vault v1.6.1 Information
 [Server thread/INFO]: [Vault] Economy: Craftconomy3 [LuckPerms]
 [Server thread/INFO]: [Vault] Permission: LuckPerms [LuckPerms, SuperPerms]
 [Server thread/INFO]: [Vault] Chat: LuckPerms [LuckPerms]

ChatControl config:

spender_abzeichen:
      Message: '&9[$]&r '
      Sender_Permission: chatcontrol.groups.spender
      Hover_Event:
        Action: SHOW_TEXT
        Values:
        - '{corpchanger_secondary_color}&m                    &r {corpchanger_primary_color}&lSpender&r
          {corpchanger_secondary_color}&m                   &r'
        - ''
        - '   {corpchanger_primary_color}&lCorp &9bedankt sich bei &f&l{essentials_nickname}'
        - '          &9für die liebe Spende!'
        - ''
        - '{corpchanger_secondary_color}&l>> {corpchanger_primary_color}Klick für
          Infos zu Spenden'
      Click_Event:
        Action: OPEN_URL

EssentialsX config:

    Admin: admin
    Supporter: supporter
    Officer: Officer
    Stift: stift
    Azubi: azubi
    Journalist: journalist
    Baumeister: baumeister
    Urgestein: urgestein
    Legende: legende
    Elite: elite
    Super-Member: supermember
    Ehren-Member: ehrenmember
    Pro-Member: promember
    Member: member
    Gast: default
    Mulch: mulch
    Tourist: tourist

I just want to clarify the main statement:
When adding the parent 'spender', everything's working fine upto the point when the player relogs .
After a relog, the primarygroup switches to 'spender'.

After typing /lp user [user] parent add spender and before relog:
https://prnt.sc/is6esc

After relog:
https://prnt.sc/is6ej5

It seems like the primary group is switching between relogs.

Are you perhaps using any default assignments to change that, or any extra plugins which modify that?

This configuration option also makes a difference.
https://github.com/lucko/LuckPerms/wiki/Configuration#primary-group-calculation

Depending on what that's set to, it's important to define weights for all of your groups.

Obviously you hit the nail on the head :D
The weight for the group spender wasn't defined, the primary-group-calculation was set to 'stored' and there was a default assignment for setting the primary-group spender with the condition 'group.spender'.

I gave the group weight.5, set the primary-group-calculation to parents-by-weight and removed the default assignment and now it works!

Thanks very much for the fast support! :)