/ignore doesn't work on nicked people.

[akyuvar]

It does say ignored but it doesn't actually ignore the person and you still recieve messages from them.

[McPlayHD]

What happens right now is that you are essentially ignoring the nick and not the player behind the nick. So messages written by the player are not filtered since the sender is still the player itself.
I could try to ignore the player behind the nickname instead of the nick when using /ignore <nick> but the issue with that would be that then in /ignore -list you would see the actual player's name, thus exposing the nick.
I think the best solution would be to not only check if the original player is ignored but additionally if the nick is ignored. So it can then happen that if a different player receives the same nickname in the future it will also ignore their messages for you. And if the original player unnicks you will see their message again.