Dropdown menu doesn’t show 2nd submenu

I have a dropdown menu on one of my sites that will only the first two levels of the menu, but not the third. The side navigation menu shows the third level, but not the dropdown. I’m using the Nisarg theme.

This is the site: https://www.mainelongrangeenergyplanning.com/

Under the top nav for “Energy Quest Report,” Appendix F should open to show the four items under it.

Any suggestions?