[Bug] Can't cast to child Blueprint

We have a Character blueprint called UnitBP.

If I make a subclass blueprint from the UnitBP, say UnitBP_Child,
and then take a Object, or a UnitBP reference and use cast it will not compile.

Oddly, the console says “Info [0791.98] Compile of UnitBP successful! [in 1,242 ms]”
but the Compile gear icon in the editor stays with a yellow question mark.

The underlying problem is that returning a child class reference to a the parent class and using the child class
has the same wierd compile issue.

Like this… (The Set of A is to force the Core reference to an Object to test the cast.)

The error log…

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