The curiously slow case of Gradle 6.3 + JDK 14 + Windows

I enabled on a large project Gradle 6.3 + OpenJDK14. The build runs faster on Mac and Linux w.r.t. JDK11, but it’s much slower on Windows, approximately a 2x factor, enough for this project to take more than 50 minutes to run on Travis CI, hence getting killed.
The only difference between the Windows build and the other two is that the latter use the daemon, the former does not. Can this be at the root of the issue?
Why it does not happen with JDK 11, then?

More information: I ran a lighter build on Windows + JDK11 and Windows + JDK14. There is a 3x difference in performances.
Here is the build scan for the JDK11 version, and here is the one of the JDK14 version.

In both cases the daemon is disabled, I’m really puzzled at this behaviour.

I just tried with the daemon enabled: same result.
It must be a bug affecting Gradle with the last JDK under Windows.