Uncurried external function with @unwrap polymorphic variant argument does not unwrap in output

[illusionalsagacity]

Thank you for filing! Check list:

• [x] Is it a bug? Usage questions should often be asked in the forum instead.
• [ ] Concise, focused, friendly issue title & description.
• [x] A minimal, reproducible example.
• [x] OS and browser versions, if relevant.
• [ ] Is it already fixed in master?

Using 9.1.3 in the example but also does not compile as expected for 10.0.0-rc.1

example here