I've run into what seems like a bug. The radio control is 'remembering' the previous selected item under certain conditions.
SharePoint has a choice column, RadioBtn, set to radio button, with three choices, "once, twice, thrice" and no default:
In PowerApps/Customize Forms, I added the radio control to the RadioBtn data card below the combo box, set the Items property to the same as the combo box: Choices([@radioButtonToPowerappsTest].RadioBtn), and set the Default property to ThisItem.RadioBtn.Value:
When I browse through each option, the default is shown correctly at first:
Click test 3:
But as soon as I click the first record with a blank RadioBtn, it 'remembers' the previous selected option, even though it is quite clear Thisitem.RadioBtn.Value is indeed blank:
If I click the next item, 'test another blank', only then does it correctly show nothing selected:
Then if I click item test 1a:
and follow that with clicking 'test another blank':
If I keep clicking 'test another blank' I get same as above. Only until I click 'test blank' the radio button options clear:
I'm sure there is a method to 'reset' or force this control to behave; I'll work on that later today. But this certainly appears like buggy behavior...however I'm probably doing something wrong so please let me know!