If I change (in DVDpedia, for instance) the Release field from "%b %Y" to "%d %b %Y", some but not all of the records in the data base will have their day field reset to 01. I find this bizarre, because that looks like a display specification, which should have no effect on the actual data.
Changing the location of %d, as you might if changing to US style dates, also resets dates. I tried this in CDpedia, it breaks the Release Date but not Original Release Date.
Pedias reset dates when they shouldn't
Re: Pedias reset dates when they shouldn't
It is indeed a display format specification and will not affect the dates already stored. If you have only "%b %Y" and you then modify the date the program stores the first as the day as it was not present in the information. There should also be no issue with the ordering of the day and month. If you continue having problems, let me know what are the exact steps to repeat a day reseting to the first without modifying it, once I can repeat I can look for the bug.