Just the one branch seems to be drooping as a result of the overwatering.. this has me puzzled, wouldn't the whole plant have suffered the same effects? Why just one branch? Anyone else have this experience? Could it instead be bud rott or something more sinister? Any help would really be appreciated. Also im aware i was overdoing the magnesium during early flower and have since rectifyed the dosage. Also its unlikely to be heat/light stress as other branches are much closer to the light than the one im having issues with.. also fan on the other side so not wind burn.. thanks in advance

I see that happen with the lower softer branches. And don't lift back up especially in flower with added weight. I'd stake it up so you don't find it hanging down over the pot.