Help! Title via ebub-name not longer working

[engine5]

Hi,
I've big Trouble! Since 1,5 years I'm reading Perry Rhodan. As I'd massive Problems to read it on my H2O because of sorting (more that 2600 epubs) I'd searched for a solution how it's possible to sort all epub in the right order. I'd found a tip that it's possible with calibre to Import the epubs (Original Filename i.e "0002 - Die dritte Macht" and if the files are pushed to the device they will be renamed in a Format which is programmable, in my case I'd choose Series number followed by Episode Name, "-0002- Die dritte Macht" so that the leading zeros won't be trunkate and if I choose "Books" and sort by "Title" I've all books in chronological order.
That have worked fine, on H2O and my new Aura One -until today!
I've to say that it have also worked fine the first days with Aura One. Just pushed the files as the last years to the device, disconnect, Content will be processed, all OK.
But as I tried to mark the first 330 books as read via Setting the ReadStatus to "2" in the sqlite DB with a Tool and has made a Little mistake (just marked also the preinstalled books as read -not really an issue) I'd reset the Aura One, and pushed the book again. But now the leading series numbers are not displayed in the Title!
I've tried everything! Deinstalled calibre, reinstalled it. The old Version from 2015, installed it new on another PC, copied the epubs Manual with the Name, tried it with the old H2O, and several other things.....
Also to copy the original files from the .zip which I'd received from my friend onto both devices -nothing works!
What can I try that I'm able to sort the epubs in old type?
What me really wonders -I was able to make it several times since last week when I've received the A1 (also read 3 books in that time with it) -and "Bam!" it's broken. Equal if I try Reset Firmware, with update to 4.3.89xx or make new to 4.3.9084, equal which device....
May it's a Problem with the Kobo-account?

[rashkae]

It's your Calibre plugboard. That's where you configure the option to change the title when sending books to the device. What did you change in Calibre?

[engine5]

Id set under Preferences, Import/Export, Sending book to device Parameter {series_index:0>4s| -|- }{title}
And it works -the book is stored on the Reader with wanted Format -but the .epub Name isn't shown under "Books".

[engine5]

Yesssss!!!! It Works now!
Thank you very much! The buzzword "plugboard" had let me search for it, so I'd make a new template and it's working fine now.
But wondering what happen -I didn't changed anything there (wasn't Aware that this exists before you named it). May because of an Background update?
Thank you very much again!