The replacement probe has a 12.8mm OD. The original is 12.0mm. The opening into which the probe fits is 12mm ID. The new probe sits proud of the opening blocking the threads from engaging. The new probe alse has a shorter hex head and a noticeably longer threaded section. Finally, the probe isn't attached to the threads.
Am I supposed to shove it in harder? Is the threaded portion supposed to crust the top of the probe to create a seal?
FWIW, I don't see any for sale that look like the original.