Using CommutativeAssociativeBinaryOperator with a BlueprintPure function causes an ensure when adding the function to a Blueprint

A UFUNCTION that is BlueprintPure and has CommutativeAssociativeBinaryOperator set to true results in an ensure whenever it is shown in the Blueprint Editor. The reproduction steps cover adding the node but the ensure will also occur whenever you open a blueprint graph that already has the node present.

Regression?: No
This also occurred in 4.18

1. Download the attached project
2. Open "TestBP"
3. Add the "Append Int Arrays" node to the graph
   Result: An ensure is triggered, resulting in a freeze for a while before the ensure is thrown and then the node is added
   Expected: The node is added without any errors or freezes