Assign background does not copy correct masters in multiple master fonts

In 1.3.7 (app store) Layers > Assign Background only copies from the first master of the target font. It would be nice if bold masters got a copy of the bold font, etc.

do you try to assign a Multiple master font to a single master?

I have tried this again several times and now it works fine now. I think I must have misconfigured something in the fonts that caused the problem.