I have an F# fable project that compiles well with the f# compiler. When I run

dotnet fable x.fsproj

on the command line that compiles within a few seconds. But when I run the same command with msbuild:

<Exec Command="dotnet fable x.fsproj" />

that hangs and never completes. What could be the issue, how to diagnose? I had similar Targets with fable that worked. I have no idea why that does not work now.