If it happens to others :
After I applied the update of May 10th 2012, an "A" started to appear after the Informations in News GK Pro.
In fact, it seems to be an error (?) in the file updated 'gk_stuff.css'.
All you have to do is to change the line
.vertical .nspInfo:after,.vertical .nspHeader:after,.vertical .nspText:after {
content: 'A';
white-space: pre;
}
by
.vertical .nspInfo:after,.vertical .nspHeader:after,.vertical .nspText:after {
content: '\A';
white-space: pre;
}
Worked for me.
Hope it could help others