Here's an alias from my Cygwin .bashrc (which took me way too long to figure out) where both the *nix and Windows style paths are invoked:
alias ms='/cygdrive/c/Windows/System32/OpenSSH/ssh.exe -A -i 'C:\Users\me\.ssh\mm-id_rsa' me@myserver'
$ tasklist /V ERROR: argument/option invalid - "C:/msys64/V"
At least for MSYS2 the environment variable MSYS2_ARG_CONV_EXC can be used to prevent conversion. https://www.msys2.org/docs/filesystem-paths/#process-argumen...
Here's an alias from my Cygwin .bashrc (which took me way too long to figure out) where both the *nix and Windows style paths are invoked:
alias ms='/cygdrive/c/Windows/System32/OpenSSH/ssh.exe -A -i 'C:\Users\me\.ssh\mm-id_rsa' me@myserver'