Could guess all day long without a diary, got allllll sorts going on, ec is out of whack means water is not flowing, waters not flowing nutrients ain't moving. Degreening all over.with no obvious starting point is micronutrients which can be common at a high pH of 7 +.
Medium has tendency to get a bit wetter during flower, phosphorus requires oxygen to uptake so make sure we are not oversaturated in rootzones, since transpiration is down its all dependent on evaporation until transpiration kicks back in.
Ignore purple 💜.
Don't blanket feed, feed based off EC.
Salts buildup until the ratio gets skewed, once skewed ph will mess things up, pH affects moisture retention by influencing the structure, texture, and porosity of the material in question, whether it's soil, skin, or other substances.
When things get too wet or too dry calcium becomes a problem when things get too wet oxygen can become scarsce preventing
Phosphorous uptake.
For all we know the only problem you have is your running a high rh and you over fed a little.
Small problems exacerbated over a period of time.
Wish you luck with recovery.