It looks like my clone is suffering overwatering. ...

A good flush, a few days for it to dry out, and then pick up your watering schedule. I cannot tell if that is two plants is a small planter, or a single one with one side LST'd down? If it is two in one planter, you should consider separating them when you transplant. Just like most siblings, two in one pot is too close. The roots will compete for space and nutrients. Either they both survive but have a much lower yield, or one will be much less robust or even die, leaving one good plant in the pot anyway. Cheers!