ExecJS parsing error in production (can't repro in dev)

heroku.log

2014-08-05T19:19:50.312518+00:00 app[web.1]: URL:  http://errbit.pre-history.com/locate/53e12e5589c5c39eff000392
2014-08-05T19:19:50.317455+00:00 app[web.1]:
2014-08-05T19:19:50.317459+00:00 app[web.1]: ActionView::Template::Error (Unexpected token: operator (<) (line: 23285, col: 0, pos: 793884)
2014-08-05T19:19:50.317461+00:00 app[web.1]:
2014-08-05T19:19:50.317463+00:00 app[web.1]: Error
2014-08-05T19:19:50.317466+00:00 app[web.1]:     at new JS_Parse_Error (/tmp/execjs20140805-21-o7l23cjs:2357:10623)
2014-08-05T19:19:50.317468+00:00 app[web.1]:     at js_error (/tmp/execjs20140805-21-o7l23cjs:2357:10842)
2014-08-05T19:19:50.317470+00:00 app[web.1]:     at croak (/tmp/execjs20140805-21-o7l23cjs:2357:19067)
2014-08-05T19:19:50.317473+00:00 app[web.1]:     at token_error (/tmp/execjs20140805-21-o7l23cjs:2357:19204)
2014-08-05T19:19:50.317475+00:00 app[web.1]:     at unexpected (/tmp/execjs20140805-21-o7l23cjs:2357:19292)
2014-08-05T19:19:50.317477+00:00 app[web.1]:     at /tmp/execjs20140805-21-o7l23cjs:2357:27484
2014-08-05T19:19:50.317479+00:00 app[web.1]:     at /tmp/execjs20140805-21-o7l23cjs:2357:29977
2014-08-05T19:19:50.317481+00:00 app[web.1]:     at expr_ops (/tmp/execjs20140805-21-o7l23cjs:2357:30735)
2014-08-05T19:19:50.317484+00:00 app[web.1]:     at /tmp/execjs20140805-21-o7l23cjs:2357:30827
2014-08-05T19:19:50.317486+00:00 app[web.1]:     at /tmp/execjs20140805-21-o7l23cjs:2357:31270
2014-08-05T19:19:50.317488+00:00 app[web.1]:   (in /app/app/assets/javascripts/ember/teams.js.coffee)):
2014-08-05T19:19:50.317490+00:00 app[web.1]:     1: -content_for :javascript do
2014-08-05T19:19:50.317493+00:00 app[web.1]:     2:   -#%script="logUsage('viewed', 'amazing teams');"
2014-08-05T19:19:50.317495+00:00 app[web.1]:     3:   =javascript_include_tag 'ember/teams'
2014-08-05T19:19:50.317496+00:00 app[web.1]:     4:
2014-08-05T19:19:50.317498+00:00 app[web.1]:     5: -content_for :mixpanel do
2014-08-05T19:19:50.317500+00:00 app[web.1]:     6:   =record_view_event('teams page')
2014-08-05T19:19:50.317503+00:00 app[web.1]:   app/views/teams/index.html.haml:3:in `block in _app_views_teams_index_html_haml__807706301997472887_69987101578280'
2014-08-05T19:19:50.317510+00:00 app[web.1]:   app/views/teams/index.html.haml:1:in `_app_views_teams_index_html_haml__807706301997472887_69987101578280'