"Installing files" step always numbered one too low on stdout (i.e. step [N/N] never shown)

I presume this is a ninja issue. If it's somehow meson's fault, I'll reopen it over there.

Using build.ninja generated by meson, I always get output like the following:

[1/5] Generating blah.gresource_c with a custom command.
[2/5] Compiling C object blah.gresource@sta/blah.gresource.c.obj.
[3/5] Linking static target libblah.gresource.a.
[4/5] Linking target blah.exe.
[4/5] Installing files.

That is: Step 5 is never shown, and the "Installing files" step is always numbered one lower than it should be, duplicating the step number of the step above it.

ninja 1.8.2 meson 0.42.1 MSYS2/MINGW64 on Windows