Spoils titles with LaTeX characters (e.g. non-English characters)

[stared]

E.g. for an entry with title:

title = {{Mafia, zdradziecka parzysto\'{s}\'{c} oraz pi}}

it produces:

'title': 'Mafia , zdradziecka parzysto\\ { s } \\ { c } oraz pi'

where it would be desirable to have its original form, i.e.:

'title': 'Mafia , zdradziecka parzysto\'{s}\'{c} oraz pi'