Forms submission list returns javascript error; unable to export

Description

Steps to reproduce

1. Go to Forms Submission view.
2. Check the first one or two form records on the top of the page.
3. Scroll down to the bottom of the form submission list => js error in console
4. Scroll up to the top again. The forms formerly checked are now unchecked, and there are JavaScript errors in the developer console.
5. Check some form records once more.
6. Try to export to an optional format (XLSX, CSV, JSON or XML). No export is made; the progress bar never stops spinning, and more JavaScript errors appear in the developer console.

Expected:
You can select form items. Also, you can export them even if there is a high number (>300) of submitted items in the list.