qbs build from scratch works as intended:

N:\.meta\qbs\.tst3>qbs --force-probe-execution profile:MSVC2019-x64
Build graph does not yet exist for configuration 'default'. Starting from scratch.
Resolving project for configuration default
svn revision: 96
N:/.meta/qbs/.tst3/default/AppVer.c4cd9211/MyAppVer.h not found
Setting up build graph for configuration default
Building for configuration default
Update N:/.meta/qbs/.tst3/default/AppVer.c4cd9211/MyAppVer.h 0 -> 96 [AppVer]
compiling m.cpp [a]
linking a.exe [a]
Build done for configuration default.

but re-run brings recompile:

N:\.meta\qbs\.tst3>qbs --force-probe-execution profile:MSVC2019-x64
Restoring build graph from disk
Resolving project for configuration default
svn revision: 96
current revision: 96
Building for configuration default
Keep existing N:/.meta/qbs/.tst3/default/AppVer.c4cd9211/MyAppVer.h rev. 96 [AppVer]
compiling m.cpp [a]
linking a.exe [a]
Build done for configuration default.

if Rule property alwaysRun changed from  'true' to 'need_update' (commented line), qbs can build _AFTER_ change:

N:\.meta\qbs\.tst3>qbs --force-probe-execution profile:MSVC2019-x64
Restoring build graph from disk
Resolving project for configuration default
svn revision: 97
current revision: 96
Building for configuration default
Update N:/.meta/qbs/.tst3/default/AppVer.c4cd9211/MyAppVer.h 96 -> 97 [AppVer]
compiling m.cpp [a]
linking a.exe [a]
Build done for configuration default.

but fails to build if revision not changed:

N:\.meta\qbs\.tst3>qbs --force-probe-execution profile:MSVC2019-x64
Restoring build graph from disk
Resolving project for configuration default
svn revision: 97
current revision: 97
Building for configuration default
Keep existing N:/.meta/qbs/.tst3/default/AppVer.c4cd9211/MyAppVer.h rev. 97 [AppVer]
compiling m.cpp [a]
ERROR: "C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30133\bin\Hostx64\x64\cl.exe" /nologo /c /EHsc /Od /Zi /MDd /IN:\.meta\qbs\.tst3\default\AppVer.c4cd9211 /experimental:external /external:W0 /DUNICODE /D_UNICODE /DWIN32 /Fda.cl.pdb /Zc:__cplusplus /FoN:\.meta\qbs\.tst3\default\a.86f7e437\3a52ce780950d4d9\m.cpp.obj N:\.meta\qbs\.tst3\m.cpp /TP /FS
N:\.meta\qbs\.tst3\m.cpp(2): fatal error C1083: Cannot open include file: 'MyAppVer.h': No such file or directory
ERROR: Process failed with exit code 2.
The following products could not be built for configuration default:
a