Apparently Panasonic has released another firmware update (9.34) to address issues with Gen-lock and external timecode.
https://eww.pavc.panasonic.co.jp/pro-av/support/cs/csregistp2m/ep2main/soft/upghpx300_e.htm
https://eww.pavc.panasonic.co.jp/pro-av/support/cs/csregistp2m/ep2main/soft/upghpx300_e.htm