Hi,
You can check this https://forum.mendix.com/link/space/microflows/questions/110651
Timestamps are always stored as UTC in Mendix, they may be converted at different points: at retrieval and at when showing.
As your result is a string, it will be no issue between the attribute you're storing the data in and the viewer.
Apparently a conversion takes place when retrieving, for which I see 2 possible solutions: