Setting FDateTime in Blueprint defaults has no effect

I have an FDateTime declared in a C++ class like this:

UPROPERTY(EditDefaultsOnly)
FDateTime StartDate;

I then set the default value in a derived Blueprint and the value is correctly parsed and will save properly with the Blueprint. However, when I try to use the FDateTime, its value is equal to whatever default I set in C++, or 0 if I leave it to be zero-initialized by the UObject system.

Why is this happening?

On a side note, is there any way we can edit FDateTimes in BP other than the current text box awkward string manipulation? There’s already a DateTimeStructCustomization class in the Engine which could be extended with some kind of calendar-style system.

Just ran into this myself in my project using 4.17. However, I checked in the 4.18 preview and it seems to be working correctly there if you’re still working on this and able to upgrade once it’s released.