As you know, in Managed Instance is possible to perform a backup and restore in the similar way that we have in OnPremise, just only we need to know that the backup needs to include WITH COPY_ONLY modifier.
I've found that restoring operation (RESTORE DATABASE databasename FROM URL='https://xxxx.blob.core.windows.net/xxxx/xxx.BAK' ) is taking a small amount of time more and checking the ErrorLog of Managed Instance.
During my troubleshooting process, I noticed that every time that I restored a database a command DBCC CHECKDB for the new database is executed.
As I found some information about CHECKSUM in the different operations done by DBCC CHECKDB adding the parameter checksum in every backup operation like this one: BACKUP DATABASE databasename TO URL='https://xxxxx.blob.core.windows.net/xxxx/xxxx.BAK'
with copy_only,CHECKSUM will prevent the execution of the DBCC CHECKDB
Enjoy!