I've got no idea.. perhaps there has been a change in the formatting? I'm fairly sure I've seen it non-bold too.
All I was doing (assuming that was just a few minutes ago; not sure of your time zone!), was deleting a duplicate thread, so I see no reason for it to be bolded.
More then likely, "Moderating" in bold is a generic coverup for members without permissions to moderate. I dont think it would be good to have it showing details about what moderating task or thread title a mod was dealing with.
VB/Office Guru™ (AKA: Gangsta Yoda™ ®)
I dont answer coding questions via PM. Please post a thread in the appropriate forum.
I believe the boldness means that they are in a confirmation screen for confirming that they are about to perform a moderation task, either that or the screen that confirms they have just completed the action.