Solved the bubble issue. Turns out there was a pinhole tear in the upper hose. However, the problem persists despite being vacuum bled. I showed the video to a local friend and we tone tested the engine harness from the ECT to the PCM again. I found no issues and the ECT is reporting the correct resistance. Leaving me with 2 final options. Intermittent fault of the Harness PCM failure. given that a temp swing of 200 to 160 would cause some kind of metallurgical issue, or at least would damage the water pump I feel... AND having probed the harness and finding it in good condition with no tears and no amount of shaking or wiggling or vibrating the wires seems to have any effect... I'm gonna see if I can get a PCM on it. Will update if I find a fix. I spoke to someone recently who had the exact same issue and went as far as replacing the head gasket which didn't solve his problem. Unfortunately, he traded the car in before it was solved. He just left it alone until he got rid of the car.