All themes and plugins usually use minified JS & CSS. The cause of your issue could be in any plugin or the theme. There is no way of telling exactly what file is causing the issue.
What causes this issue is when a minified file with an extremely long line length is uploaded and treated as a TEXT file. Some FTP applications and some hosting environments will truncate long lines in the file treated as TEXT.
This really should not happen when you update a plugin and usually only happens when you FTP individual files.
