Pg: restore backups goes into pending state

I used the Heroku PGbackups add-on to back up a database from one Heroku app to another Heroku app. But after migrating PGbackups and removing their add-on, I moved these commands to use the new commands as instructed. But now I am facing a problem with this process: sometimes pg: restoring backups goes into a pending state. The DB is cleared, but the backup doesn't copy / restore and just keeps "pending".

This is what I got when checking the status of pg: backups

At this time, Db was not overloaded with connections:

Then I used pg: wait command and previous requests failed and new ones worked fine and didn't hit pending

But I'm not sure if this will happen again.

I would be very grateful if you could explain to me what could be the cause and how to fix the problem. Thanks in advance for your time and help.