Group in material function patameter not working

When I create the material parameters in function, they are perfectly visible, but does not work grouping. However, when a conventional material parameters, all works. How to solve the problem?

Hey Othelnic12 -

Thank you for this report, we have previously identified this issue and have already worked out a solution. If you would like to get the fix earlier and have access to the Source build from Git Hub you will need this commit:

https://github.com/EpicGames/UnrealEngine/commit/477a1971839447ce86f293195f40a91b51559c56

Thank You

Eric Ketchum