calcium deficiency ? or phosphorus deficiency or something else ?

Your plants are a little bigger now, they should have a bigger vascular footprint especially at nights. Your feeding well every week. Are you being consistent with watering 10% run off? Are you checking your ph before and after? If salt minerals from your last feeding are still within the medium before you pile on the next dose you could be suffering from salt build ups, this would explain brown burnt blotches at random. Thing about watering heavily is once a canopy develops, the evaporation that would normally happen in the top 2-3 inches from lights will cease, water is the transport solvent it can only escape a number of ways either uptake through rootzones, drainage or evaporation. When you keep a daytime rh of 60% I can guarantee your night rh will rise into the 75+% especially if your temp drops. Think of rh in the substrate.... if the air around the medium is drier, moisture will very gently be wicked from hard to reach places in centre of pot to outer layer of medium, eventually wicking to the dry air in the tent. This in conjunction with maintaining a negative pressure will help you combat getting waterlogged in the rootzones. I aim to try and get the sweetspot of having dry pot every 24-48 hours regardless of watering. When you keep high rh above 60% ambient the trapped moisture in those fabric won't escape to atmosphere as the RH level is already wet enough. Oxygen to rootzones can be a limiting factor of growth often unknown or overlooked. More air on pots, little less rh, make sure to control nighttime rh as it will shoot right up during flower. Water thoroughly, making sure your not building salt deposits. Check your e.c levels. Plants look good, maybe just a couple environmental factors causing some blemishes. Wishing you very best with your buds bud, hope they make it a bountiful harvest.