Sure, this is very minor, but it is in fact a bug. If you use separate [S] tags next to each other, with a space in between, Xenforo seems to try to help by combining them into one tag. For instance: [S]one[/S] [S]two[/S] becomes [S]one two[/S]. It seems to be an issue with the rich text editor, even if entering the bbcode directly. Once I publish or switch to BBCode view, the tags are combined. If entered directly in BB Code Editor, it works fine.