I have increased post numbers to each user groups so moderators have more time to know about the users nature.
And In-order to both control spammers and members who violate forum rules i have introduced 3 new groups for manual allocation by admins (all are duplicates of "Newly registered members group"), first group is to discreetly bring users post to screening, second is to alert the user about issues, third is a warning tag. Once user avoids issues they are manually returned back to their original groups.
Now after having done that and its been several months and several forum updates have been performed. I could notice groups aren't auto changing based on post count, both for regular users and also for those who were temporarily moved to spam groups and returned back to original groups.
Please let me know the issue and suggest me solution for the same. Also let me know the best practices for user groups like number of posts per user group other than the default post count.