I think the PERL5LIB path is weird since normally it isn't needed - it's in @INC. But OP is using the Git for Windows perl, not Strawberry (C:\Strawberry\Perl\bin\perl.exe) but wants to use the libraries installed in Strawberry with the Git for Windows perl. So he has to configure PERL5LIB with paths that would normally be in @INC, but the Strawberry paths aren't in the Git for Windows perl @INC.

A bit of kludge if you ask me, I just use PowerShell (way more capable than cmd.exe and can be customized to be like bash) so I don't need to use Git for Windows bash and thus never have the perl conflict issue.