Last I checked to sum it up you had like 5 things off. Pot is too big which wont raise yield its just harder to take care of. You dont feed enough daily and to good runoff, you dont check ec runoff numbers. Adding calmag where its not needed. Dont make sure the nute dose is strictly consistent.
Id prepare my own coco to root out water logged, It can happen easy and could even overwater coco pretty easily. They say the opposite in mainstream areas but its not true. You can get bud rot this way.
Have any of these things been improved since recently? More info the better as usually its grower error. When I found my own answers it was because I didnt provide that info. Could be environment, could be neglect with bleach, could be water source. VPD off, etc.