In a 10 year old dog, I'd be worried about focal (petite mal) seizures. These aren't your full-blown down and shaking with loss of consciousness seizures; sometimes focal seizures can be just a twitching in one limb or the face, other times it can be just behavior changes, other times they can just tremble all over. Since of course she won't do it at the vets, if there is a way to video tape the episodes and show the vet it would be the next best thing. Pain is also a very good thought. We saw a dog referred to the neurology service at school for these head twitches. Turns out he had cervical disk disease and was in pain. Luckily the owner brought in a video of the dog's episodes because otherwise we wouldn't have been able to properly diagnose it without running up HUGE bills. They had already run up quite a bill at their regular vet, but didn't have the video tape of the episodes for her.

^This is what lots of the leaf nodes look like. ^This is what the inside of one of the leaf branches that is affected looks like ^Another leaf "joint" ^Part of one of the main stems about 1/4 way up the plant ^These are running most of the way up the plant...only about the upper 1/3 or so seems pretty clear of these I trimmed away most of the dead foliage and any leaf branches that showed the outward signs of the brown decay after taking these, but there are still spots along the main stem (Such as the second picture from the bottom) that are split and decayish looking. I do only have the three big plants...I suppose I can just leave it until it fully dies to see if I can get any more ripe fruit off it and discard the soil in this pot. I am still just very curious what it might be.... All my other plants seem perfectly healthy and show no signs of whatever this is. Thoughts and opinions?

I haven't seen wood with those marks. They look like cuts into the wood and could serve to allow it to dry out faster. The only wood I've seen meant for garden edging didn't look like that but it usually is treated to make it last. You could check around Bunnings or local nursery/landscape centres and see if they have something similar.

Looking at their grout chart, Stone Beach or Sugar Cookie. Are you sure your choices are Ardex? The color names do not seem to match the colors that they offer? https://cdn.ardexamericas.com/wp-content/uploads/2018/09/ARDEX-TSIS-Grout-Color-Chart-Brochure-download.pdf