TypeError: eval(…) is not a function

I’ve been using Enfold for a while on my site (love it!) but in the last week I seem to be having javascript errors. Basically my shopping cart is not working among other errors. I can fix it by reloading Enfold and Membermouse (a membership plugin). After a while, it breaks again. I reload fresh copies of the Enfold theme and Membermouse plugin and it works again. I am trying to narrow it down and I created a staging site and disabled all my plugins, including membermouse, and I have a clean copy of Enfold running. I get an error. The error I an receiving is:

Uncaught TypeError: eval(…) is not a function(anonymous function) @ wp-mediaelement.js?ver=4.3.1:3

I am not sure if this is what is causing my issues. Is this normal? Again, no plugins are installed and I have a clean copy of Enfold running on it.

Thanks!
– Dan