Fitvids.js Causing Errors in Casper 2.10.2 Theme

I am trying to modify the default Casper theme to make minor changes. However, I keep getting errors reported in the Chrome console, all but one related to fitvids.js, even when I select the unmodified Casper theme on the Design page:

Uncaught TypeError: $postContent.fitVids is not a function
at HTMLDocument. (
at j (jquery-3.2.1.min.js:2)
at k (jquery-3.2.1.min.js:2)

I have the jquery script in the Code Injection page:

Any suggestions as to how I can correct these?