Sorry, but I don’t know – I think it’s something unique to your site.
If you’d like to provide a URL or email me the source, I can try to spot it for you.
Otherwise, try starting from a simplified setup:
– deactivate ALL other plugins
– switch to a standard theme like 2014
– make your modification
Then reactivate to find where the problem lies.
If you do the above and it doesn’t work, you can also leave everything deactivated and send me a login, and I’ll try to take a look for you.