What's actually failing up there
Heat + age, almost every timeThe hardware
The blind itself is rarely the problem. It's carried on small clips, guides and carriers — mostly plastic — that sit under a big pane of glass and cook in the Australian sun for years. Heat cycles make them brittle; one day a clip lets go mid-travel and the geometry of the whole shade changes.
The sequence
It almost always fails in the same order. First a faint rattle, or a shade that sags on hot days. Then one side starts lagging and the blind skews in its tracks. Then it jams — half-open, usually — while the motor keeps trying, loading the surviving hardware until that breaks too.
Why it gets misquoted
Dealers often can't buy the broken clip on its own: the catalogue sells the sunshade as part of a complete roof cassette. So that's what gets quoted: a cassette, for a clip. A generalist who's never had one apart passes the same quote along. We've had hundreds apart.