There's enough evidence from people who take this seriously and investigate this issue with lab equipment (Der8auer, Igor or Igorslab, Steve of Gamersnexus etc) to make me generally uneasy about using even the latest H++ connectors.
Roman, in particular, released a video last week where a user sent in his GPU+PSU+cables to him for repair because the PSU and GPU manufacturer were fighting over whose responsibility it was and neither of them would honour the warranty because of this. The cable was fused to both the PSU and the GPU and it was very definitely inserted all the way. Rather than a faulty cable or poorly insterted cable creating a local hotspot, this was irrefutable evidence that the user did everything right and the fault lies with the design of this standard allowing too much current to flow over an individual wire.
Roman isn't the first person to show fully-inserted melted connectors and unless something changes with the design he won't be the last. It's not a PEBCAK error and 0.3% failure rate still means 1-in-300 GPUs will catch fire which translates to hundreds or even thousands of graphics cards across the whole industry, each of which could potentially result in someone's house burning down.
There are already dozens of photos of MSI's latest yellow indicator cables melting, despite none of the yellow warning indicator being visible. People have gaslit users for failing to insert stuff correctly, using aftermarket cables (which are typically built to a higher standard than the free cables that come with a PSU anyway) and tight bend radius near the cables, but it always boils down to the same issue - there is overwhelming evidence out there in photos and videos to prove that most of this PEBCAK gaslighting is unwarranted - the connector design is faulty and more GPUs continue to burn with every passing day even with all these minor changes to the standard to help prevent the problem.
I use my 12V6X2 cable because I have no choice in the matter, but even at just 300W it makes me uneasy - I've seen multiple pieces of content now showing that the current is often distributed unevenly across the individual wires, and as an engineer I understand how temperature and resistance imbalances in (and here's the important part) an UNMONITORED cable result in a positive feedback loop where the hot wire has higher resistance which makes the wire hotter, which increases its resistance. They're all accidents waiting to happen IMO, it's simply a question of time.