Would it be ph fluctuations?
I added fresh warm coffee grounds,biochar & seaweed 1-2 days before this happened.
Yesterday I well fed my cannabis sativa (Wikipedia) plants with fresh shredded extra roasted Starbucks coffee under the assumption they will grow better, but instead of that this morning I saw the ...
gardening.stackexchange.com
pH fluctuations may be a side-effect to it. thing is that the initial breakdown of organic matter largely involves fungi (mold) and also "bad" microbes (anaerobe bacteria) which do create a kinda hostile environment for your plants.
Usually when one does composting of green garden stuff or organic kitchen leftovers, these guys are, at some point, repressed by the good microbes and then, ther organic compounds are also made more available.
Although the last poster of your link arrives at the right conclusions, he also does confuse something:
"
Cannabis plants like a more neutral to ALKALINE soil, NOT at all a neutral to ACID soil. "
When, in fact:
Soil: pH ~6.5 ( 6.2 - 6.8 )
Hydro/ "Soilless": pH ~5.8 ( 5.5 - 6.0 )
Greets