Error with shape and position of a post

To see how this works on this forum

and the same with BBCode disabled:

On our forum we had a strange error when we use the BBcode for center and scroll in the wrong order. Just this way:

[center]part1 [scroll][/center] part 2[/scroll]

Then the profile information of the person who posted it came below the post instead of to the left, and the next post came to the left of it, just where the profile information should be. Can that be an error in the php-software?

apparantly it works here the same way