PowerApps Date Only field showing wrong date, but only for certain dates

Landon: 19 May 2022

this is stumping me - I have a canvas app which connects the a SharePoint Online list. In my list, there is a "Date Only" field, which is displayed on the PowerApps form. The formula for Powerapps is: Text(ThisItem.DateOnlyFieldInQuestion,"dd/mm/yyyy","en-US").

Now, this works perfectly fine for all records... except for any in which the SharePoint date only field is exactly "07/10/2018" (i.e. 7th October 2018). In PowerApps, this displays as "06/10/2018" (6th October 2018, the day before) for some reason.

If I update the formula to include the time (Text(ThisItem.DateOnlyFieldInQuestion,"dd/mm/yyyy hh:mm:ss","en-US"), then the date is displayed as : "06/10/2018 23:00:00". For all other records, the date is correct and the time is 00:00:00, which is what I would have expected for a Date Only field. For example, if I manually enter 6/10/2018, it correctly shows 6/10/2018. If I enter the day after, 8/10/2018, it shows the correct date 8/10/2018.

After further investigation, it seems the issue affects the 1st Sunday of October in any year (e.g. 2nd October 2016, 1st October 2017). Haven't identified any other dates that might trigger it.

I'm a bit stumped, is there something unique about that time and date? Does this sound like a bug? Thanks in advance for any assistance!

Emma: 19 May 2022

Sounds like it could be related to Daylight Saving time. Is your SharePoint site set to an Australian timezone?