"Syntax error, unrecognized expression" error on clicking remove

There's an issue with one of our content type when clicking the "Remove" button on added taxonomy terms - we get the following error:

"Syntax error, unrecognized expression: #"

Tracing through the javascript execution, the error fires during the re-binding of Drupal behaviors, after the ajax request returns with the new HTML.

We thought it was related to http://drupal.org/node/1315192, but after wrapping all our attribute value selectors with double quotes, this didn't fix the issue.

In the end, we threw a try/catch blog over the "Drupal.attachBehaviors(Drupal.HierarchicalSelect.context);" line in hierarchical_select.js to catch and dismiss this particular error, while throwing any other sort of error that comes through.

Patch(es) to follow, once I have an issue number after posting this...