Dashboard>Server Settings>Cron Tab for Users (expanding cron list disappearing)

Hi guys,
The expand option for crontabs is not working properly in Google Chrome Browser.

If i go to dashboard>Server Settings> Cron Tab For Users , and then click on the + to expand, the list displays only for a second before disappearing again.

I have screenshotted the expanded list immediately after clicking on the expander and a fraction of a second before the list disappears ...

https://drive.google.com/file/d/1D0inks7QFv3bCMOX50bsLzbPqxR5QqOb/view?usp=sharing

 and the second image link shows the missing list "WITH" the expander enabled...

https://drive.google.com/file/d/1Mt2oJUFUJNbzx_WLYm03AGwsFe27cAUE/view?usp=sharing