MacBook Pro A1708 Kills USBC devices repair

Problem description

 * 1) incomplete

Provide a concise description of the issue here. Be as specific as possible to help readers quickly determine whether or not this is the exact problem they are facing.

Symptoms

 * Kills USB-C devices

Solution
Make sure that 20 V is only present on C3101 OR C3201 (PP20V_USBC_XA_VBUS OR PP20V_USBC_XB_VBUS). If A is making 20 V on B, or vice versa, likely need to replace the MOSFETs Q3100 and/or Q3200, since they're letting 20 V through (backwards!) when they're not supposed to.