Exactly. When I use polish button, it polishes only epub.
Steps to reproduce:
1. grab epub here
https://www.gutenberg.org/ebooks/5154
2. drop into calibre,
3. convert to mobi,
4. polish book
The window displays only epub polish logs:
https://imgur.com/a/YcHzRNL.
original_epub confirms that epub file has been polished, but original_mobi doesn't exists. Viewing each file confirms this situation.
Weird: If I only convert epub to azw3, it polishes epub and azw3!
Code:
----------------------------- REPORT ------------------------------
## Polishing: EPUB
### Updating metadata
Metadata updated
### Setting cover
Cover updated
### Inserting metadata jacket
Metadata jacket inserted
----------------------------------------------------------------------
## Polishing: AZW3
### Updating metadata
Metadata updated
### Setting cover
Cover updated
### Inserting metadata jacket
Metadata jacket inserted