Hello Hanumath,
this behavior is really annoying.
It seems like the PID stops being activated on its own.
This happen to me all the time in Tests system, but weirdly, it never happened in Prod. There might be some better back end in Production systems. Hopefully!
If someone got a fix from SAP to solve this, do not hesitate to share it. 
Thank you for your attention.
Best regards.
Jacques-Antoine Ollier