"G-Central does not name the source of this leak."
Oh c'mon, please don't be silly. You can just simply take a look at the user manual, which is publicly available on the Casio website:
casio.com/content/dam/casio/global/support/manuals/watches/pdf/35/3575/qw3575_EN.pdf
casio.com/content/dam/casio/global/support/manuals/watches/pdf/35/3578/qw3578_EN.pdf