Anti-Spam Bug?

[Phil7789]

Hey there,
im not quite sure if it is a bug i had yesterday on my ts3 server.
I wanted to block some channels to users with insufficient "channel join power" so i edited the "needed channel join power" for each channel and let a friend of mine test it. Well he was not able to move to the channels, fine so far. The problem now is that he tried "desperatly" ^^ to get into the channel -> he "spammed" it although he was not able to join.

The result was that he got banned from the server due to spamming, fine. But after i deleted his ban he was instantly banned again in the moment he connected to the server, even deleting the "needed join power" and the channels could not help unless i gave him server admin rights.

Only a restart of the entire TS3 Server could solve the problem, as he could not connect any longer being a normal user.

Is this a wanted feature or is it a bug?