Ajax error Adding file into folder inside file section..An illegal choice has been detected. Please contact the site administrator.

Hello,

Creating folder and attaching file into folder working perfect for my open atrium site. However creating file section -> creating folder inside file section -> adding file into that folder is not working fine.
I created a file section name as test (see attached image file_Section.PNG). than I created a folder t2 inside it. that worked perfectly fine. when I tried adding files into folder t2, it's not working (see error1 and error2). it's throwing error and if i'm clicking again it is bypassing error and i'm not able to find my folder t2 inside test file section.
It looks like a ajax error. when it's attaching media field it's not allowing "test" section under "openatrium section" (see image error2)

please suggest?