I had to manually upload a .fit file and it now has the wrong date
File date is 5/24/2016 (today is 5/25/2016) and garmin connect thinks the activity was 6/2/2016
Forerunner 225 thinks the activity was today in history
Can you not go into web Connect, open the full page on the activity, click the pencil icon top right and adjust the time and date just above the title of the activity on the upper left?