I'm glad you narrowed down what was causing this issue and may be able to salvage some of that effected bud. Your analysis was thorough and very logical with where and how the water was pooling. These effects do look like some overwatering, but wow the impact was pretty drastic with the foliage turning brown and crisping.

Really glad you got that moisture meter and I hope it works great for your purposes. It should give you a pretty good pH reading as well.

I was taking a look at the seedfinder link (which I find to be one of/if not the best genetics cataloging on the internet) and noticed the South African Sativa genetics. I was prompted to look by the sativa structure this plant has. Despite it being a balanced hybrid, it seems sativa traits are very dominant in some phenotypes. I would agree that this is causation for the need for less water.

You've been doing great work with this grow despite the challenges along the way, and I know you're going to harvest some amazing bud from this grow. Awesome update man.