Committing Jupyter Notebook doesn't render all equations in Bitbucket UI

Issue Summary

This is reproducible on Data Center: (yes) 

Some equations that render properly in Jupyter Notebook, don't render in Bitbucket UI.

Steps to Reproduce

1. Commit a file (<<filename.ipynb>>) with Jupyter Notebook content in local repository
2. Push to a remote repository 
3. Navigate to the repository and open the recent file committed.

Renders as expected:

$$ \sum \limits _{1}^{7} X{e^x} $$ 

Does not render as expected:

$$ \sum \limits _{1}^{7} X_{14}{e}_{j} $$

Expected Results

Rendering of all mathematical symbols. 

Actual Results

Text representation of mathematical symbols, in some cases. 

Workaround

Currently, there is no known workaround for this behavior.