If you create a sticker with a barcode and add numeric values to it, such as isbn, then there are no problems when generating a pdf. But if you include text data in the sticker, such as title or author, then when generating a pdf you get a zero size and no data.
Not every barcode type supports alphanumeric characters, most likely you picked one that doesn't. Which one are you using?
I checked with all barcode options - it doesn't work.
The label printing can be tricky and it has a lot of options. I think this would be better suited for the chat, but we will need the exact settings you use and the change you make that breaks things.
Ok