Bug Report: I think Dropdowns are malfunctioning with newest release

For a short period of time, perhaps since we upgraded to 21.3, I've noticed a strange behavior with Dropdowns.

When I pass a null value, I get a pink box that says I need to provide a placeholder text.  This is expected.  However, now, when I DO provide the placeholder text, it still complains in a completely different error that simply states that it has received a null value.  But dropdowns with placeholder text are SUPPOSED to accept null values.  I haven't found a way around the issue except to trick it into working by making sure the value is never null, and providing a value to replace null if it is.

Basically, placeholder text now seems to be useless.  Is this an Appian bug?  Does it work differently now?  Are placeholders redundant?  Is it the 21.3?