3.0.17-1 Nightlies don't match 3.0.x branch builds

[offtrack]

I'm compiling 3.0.17-1 (win32) to test some patches before the official release, but the result is different than what's in the nightly builds. For example, a years-old bug that outputs silence after seek operations to "DirectX audio" (but not to "WaveOut audio") based on the Input "File caching (ms)" duration is mostly fixed in nightlies such as this one, but that bug is still present in my builds.

The Docker container used is the only one listed for "vlc-debian-win32-3.0":
https://registry.videolan.org:5000/v2/v ... 1008142723

I tried this once before building:
git clone --single-branch --branch 3.0.x https://code.videolan.org/videolan/vlc.git

I tried this another time:
git clone https://code.videolan.org/videolan/vlc.git
cd vlc
git checkout 3.0.17-1

Builds were done from the "vlc" directory using:
extras/package/win32/build.sh -a i686 -r

Before each new build any existing "vlc" directory was completely removed.

The builds succeed, VLC works and claims to be 3.0.17, but as I said there are still bugs present that the pre-built nightlies don't have, and my "release" builds are quite a bit smaller than the "nightly-win32" release builds as well (for example, the whole .7z archive is 2MB smaller, and libx265_plugin.dll is about 600KB smaller).

Am I missing something obvious? Or are the nightly binaries based on code that hasn't been published yet?

Any help would be welcome.

Thanks!