The issue was solved by opening a ticket at MS support.

After a week or so they replied that it was identified as a bug within SQL Server and that it...

thank you very much!!!!

Server: Msg 8966, Level 16, State 1, Line 1

Could not read and latch page (1:1610) with latch type SH. sysobjects failed.

Same error...

Even if i change the backup to a local drive.

When i backup without the checksum option, the backup runs ok...