disappearing of services from data tab in thingworx 8.4

Hi,

We faced a issue where suddenly the services in data tab got disappeared and we couldnt retrieve them. But the connection exists for all widgets which we could see from the connection panel in bottom but the data tab is blank. 

Another issue we faced is,when we duplicated the mashup there was thing called multiple times and services called multiple times which we did not use at all. Also when we switch from one mashup to another and come back to the mashup in which multiple were called, the data got disappeared. 

Is there any way to recover this issue and why is this issue occuring in thingworx more often? 

Thanks,

Shalini V.