Equation parsing problem

[rreusser]

This equation succeeds:

[Equation display:`true`]
\sum_{j=0}^n x^{j} + \sum x^{k}
[/Equation]

and renders like this:

While this equation fails:

[Equation display:`true`]
\sum_{j=0}^n x^{j} + \sum_{k=0}^n x^{k}
[/Equation]

and renders like this:

It seems like maybe the _ is interfering with markdown parsing, but I'm not 100% sure yet.

As usual, work around is [Equation latex:"..."/]