windows paths messed on recursive maven exec

I am using exec-maven-plugin to run another maven build from within maven.
When I run maven on Windows in git-bash with custom settings like this:

export MAVEN_ARGS="-s /d/projects/mmm/conf/.m2/settings.xml"

I get this error:

[INFO] --- exec:3.1.0:exec (Install test project) @ mmm-code-java-impl ---
...
[DEBUG] Executing command line: [C:\WINDOWS\system32\cmd.exe, /c, D:\projects\mmm\software\mvn\bin\mvn.cmd, -X, install]
Apache Maven 3.9.6 (bc0240f3c744dd6b6ec2920b3cd08dcc295161ae)
Maven home: D:\projects\mmm\software\mvn
Java version: 21, vendor: Eclipse Adoptium, runtime: D:\projects\mmm\software\java
Default locale: en_US, platform encoding: UTF-8
OS name: "windows 10", version: "10.0", arch: "amd64", family: "windows"
...
[ERROR] Error executing Maven.
java.io.FileNotFoundException: The specified user settings file does not exist: D:\d\projects\mmm\conf\.m2\settings.xml
    at org.apache.maven.cli.configuration.SettingsXmlConfigurationProcessor.process (SettingsXmlConfigurationProcessor.java:91)
    at org.apache.maven.cli.MavenCli.configure (MavenCli.java:1084)
    at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:279)
    at org.apache.maven.cli.MavenCli.main (MavenCli.java:206)
    at jdk.internal.reflect.DirectMethodHandleAccessor.invoke (DirectMethodHandleAccessor.java:103)
    at java.lang.reflect.Method.invoke (Method.java:580)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:283)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:226)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:407)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:348)

I already filed an issue for maven core but no feedback for 1/2 year:
https://issues.apache.org/jira/browse/MNG-8018
In that MNG issue, I even attached a ZIP with a minimal project and script to reproduce the error.

It would be lovely to get some feedback (already error confirmation would be helpful).

Start with the linked Maven core issue MNG-8018 and its attached ZIP reproduction. Run the supplied project and script on Windows from Git Bash with MAVEN_ARGS set as shown, then compare the recursive exec behavior with the reported path conversion. Done means confirming the failure and documenting a clear next step or fix scope.