This is strange: I am importing date ranges per Import from CSV with the date format as “DD Mmm YYYY - DD Mmm YYYY”. For some reason, the imported range end dates are one day earlier.
It’s possibly an effect of the way date ranges are stored:
https://the.fibery.io/@public/User_Guide/Guide/Date-Ranges-in-Formulas-42
Are you saying it’s a bug or “working as designed”? If the latter, then recommend Import from CSV be updated to clarify this point.
I would say it’s a bug (and let’s hope a dev can fix it soon 
)