Image rotation fails to regenerate custom sized thumbnail

I’m using custom image dimensions in functions.php like this:

add_image_size( 'custom-size-thumbnail', 120, 120, true );

I uploaded some pictures with wrong orientation, so I used “edit” options to rotate them…

Problem is, that only original size pictures (full, large, medium, thumbnail) are regenerated (as a new file in the FTP directory – original picture.jpg, rotated picture-e1384125509778.jpg). My custom sized, however, are not 🙁 (no new file is created, theme is still loading one with wrong orientation).

Any idea how to fix this?

Thanks