It seems You are getting the errors due to some corruption on the source db at 12.5.3 server.
Can you please run the below checks on source database :
dbcc traceon(3604)
go
dbcc checkcatalog(db_name)
go
dbcc checkalloc(db_name,nofix)
go
dbcc checkdb(db_name)
go
If you find any issues in any of the outputs, Fix it first. Then take the dump again (preferred in quiesce mode) and restore to the 16.0 server.
Let us know if this is helpful.