I've noticed that from time to time modlog isn't showing the recent bans, and some of the banned profiles remain with signatures.
I thought modlog is the most recent update at realtime. But from what you experienced it looks to be false.
Perhaps this is due to the fact that forum staff are using the different methods for bans.
I think there are only two methods for ban.
1. Temporary Ban ( 7 days mostly )
2. Permanent Ban
Please correct me if there are more ways. Also I cannot see how would this effect the modlog.