To avoid this issue, do not manually copy the project when a process is running.
"Save Project As" can still be used to copy the project but not to stop the current run.
"Save Project As" closes the original project in the current Vivado GUI but does not stop the current run.
It appears that the other project is closed, but if you launch another Vivado, open the original project and monitor the original run's log, it will show that the run is still going on .
When the run completes, you can use the corresponding files for analysis which are located in the synth_x/impl_x run folder, such as .dcp, .rds, .rpt, .log, and etc.