I know of just one UK 245 GTI that this has happened to. Unfortunately this resulted in the outcome that you described at the start. Pot luck as to whether you catch it in time or not. It seems pretty rife in the US though so I can’t work out why it happens so much there but not here. The UK VW Tech who repaired the one I know of said that the radiator set up is very similar to mk7 - I’m not sure if they failed on these too or it is mk8 specific. I’d also be interested if any of the other evo4 EA888 applications have the same issue (S3, Octavia vRS, Cupra Leon)
Certainly something to keep an eye on and badger VW UK with if it becomes a thing. Such a simple plastic clip causing a catastrophic breakdown isn’t really acceptable