"Related" tab in app

"Related" tab in app

Dear community  

We are freshly using the Zoho CRM app, and are encountering an issue:
In the app, several times over the last couple of days the "Related" tab in our Leads module comes up blank, showing no info nor having the possibility to add any events or tasks. The "Details" tab is showing all proper info however. 
The only solution so far was to reinstall the app all together.

Is this a known bug?
Are we doing something wrong? 

It happened on several devices, both on Android and iOS. 

Thank you so much for any help. 

Regards, 

Remco