Tag appearing in some posts

[luckylinux]

Hello
I just would like to get help for a problem which affect me after upgrading to 3.7.1.
http://www.tuttoforum.com/novit/399-...m.html#post603
The problem is (now) that on certain posts (the ones with a single line of writing) a "</div>" tag is appended to the end of the message and posted into the database, as part of the post.

About the same happens when editing posts throught the advanced interface: if with the inline ajax editor all goes ok, when editing with this advanced interface a "</div>" tag is appended to the end of any post.

Some data:

• PHP 5.1.6
• VBULLETIN 3.7.1
• MYSQL 5.0.42.x
• The support ticket team said that this happens with the template I use (custom, based on kirsh) and not with the default template
• Both with plugins enabled or disabled this happens
• If I turn the WYSIWYG editor off, everything is OK

Any other forum admin has the same problem ?
I see this problem only after gone to 3.7.1, as well as it could be with 3.7.0 (no idea).
Can you help me ?
I tried to edit the "editpost" and the "editor_smiliesbox" template and replaced with the default template.

Also: the "</div>" tag at the end of the post is posted in the database as part of the post (as said before) and it's a STRING, it's not a "hidden" HTML tag.
Thanks

Luckylinux