Although I cannot confirm if this is a bug with HANA Revision 72 or 84 as I did not come across it, I can definitely tell you where to look for to tarck the progress of the recovery
From HANA Studio-> Diagnosis files-> backup.log
This file should tell you the progress of any backup or recovery tasks that are running or occurred in the past
The good news is even if the HANA system is inaccessible(as in Hardik Patel's case) you can connect to the HANA studio using the SIDADM user and open the connection in DIAGNOSTIC Mode to check this backup.log file
My recovery screen had been accidentally closed during a Production to Non production refresh and I had to use this log to track the progress as the HANA system is inaccessible during the refresh
Hope that helps