[Koha] Dewey Number does not show up for Items even though available in 082a Tag.

Hello, I am working with Koha 3.14 on Ubuntu ( installed via packages) I have a strange behaviour, reg- class number display. I am updating Dewey Number in 082a field for a record. and after adding multiple items to the same record, items do not show up Dewey Class number in OPAC or in Normal View. I would like to know, why it is happening? For fixing this, I am doing, "edit items in batch" and updating dewey once again at "full call number" for all the items. then it displays in opac. How to avoid this ? Do we have any settings koha? with thanks. Satish MV Librarian Govt. Engineering College Hassan, Karnataka. --