[OS X TeX] A bug in TS?

[Warren Nagourney]

Hi,

I am using TeXshop 2.18 on  a Powerbook running 10.4.11. When I  
typeset the following sentence, a leading "1" in the formula is left  
out:

The damping time is $1/\zeta\omega_n=(1/\tau+\sigma\Gamma n_0)/2 
\approx 10^{-9}~\mbox{s}$.

However, when I put a space after the first $, it works correctly. I  
typeset the same document on a Latex machine (using Kile) and it  
worked properly without the space (as it should). In other cases,  
leading characters in online equations usually do not cause problems  
(it failed in another case with a leading numeric).

When I use the LateX Equation Editor, it works fine, so it is not the  
TeX engine, apparently. Also, in a fresh document, things work properly.

Does anyone know what is going on?

Thanks.

Warren Nagourney