well, this is how you can get the bug:
1. Insert a custom emoticon, and make it's keyboard shortcut to be one character. like "g" "!" "6" (without the quotes) or anything like that...

2. Go to the Plus! Preferences window, go to Instant Messages and then to Word Filtering and click Add.

3. In the window that just appearead, enter the following settings:
Filter this word: Test_abc
Replace by: Test_xyz
Direction of the filter : Messeges you send

Now Click OK and then OK again.

4. Open a conversation with somebody, and send the following message:
"Test_abc !"
(assuming the one-character shortcut of the emoticon you've added is "!")

The result:
The emoticon is not shown, and replaced by a space. Emoticons that have a keyboard shortcut of 2 characters or more show just fine after a word filter.

i've replaced the ? and ! characters with emoticons, and this bug is annoying

I hope i explained it well and it will be fixed soon! thanks

Edit: Forgot to mention i'm using MSN Messenger 6.2 in Windows XP...

so in other words..its filtering out lines..

what happenes when u use messenger emotions such as

they all work...and regular custom emoticons too. just one-character ones don't work :/

Don't triple post: it's against forum rules.
As for if the bug's going to be fixed in the next version of Plus, only Patchou can say. Then again, he may keep quiet about it.

yes, this should be fixed in the next version, sorry about that