[XeTeX] is this a bug?

[Mike Maxwell]

The following minimalist document:
-------------
\documentclass{report}
\begin{document}
\paragraph \begin{table}[H]
\end{table}
\end{document}
-------------

results in the error msg:
-------------
! Argument of \begin has an extra }.
<inserted text>
                 \par
l.5 \paragraph \begin{t
                        able}[H]
-------------

Avoiding the error msg requires either some text in the \paragraph, or 
else \paragraph {}.

Is this correct behavior?  Why is the above considered wrong?

The above doc is of course not good for much except illustrating the 
problem.  The original had text in the paragraph, but the text followed 
the table.  Perhaps not the usual way to start a paragraph, but no more 
*wrong* than using a preposition to end a sentence with.

(And how do these error msgs get generated, anyway?  Why the carriage 
return(?) between the 't' and the 'able' of 'table'?)
-- 
    Mike Maxwell
    What good is a universe without somebody around to look at it?
    --Robert Dicke, Princeton physicist