Beta.TSA.gov_9_2015 - "+" function to drop down Travel section inside "hamburger" menu not working

Device Make: iPhone
Device Model: 6+
Device Operating System Version: 8.1.3
Browser: Safari
Carrier (or WiFi): Verizon
Severity: High
Description:
When opening mobile "hamburger" menu and trying to drop down Travel menu section with "+" function, submenu does not drop down unlike other sectionn (e.g News, About)

Steps To Reproduce:
1) Go to beta.tsa.gov
2) Open mobile "hamburger" menu in upper right corner.
3) Click on "+" link next to "Travel" to see Travel sub-menu.
4) Travel sub-menu does not drop down.

Expected result: Expected Travel sub-menu to drop down after clicking on "+" link next to "Travel" menu section.