Yes, this is about Canon lenses - one model in particular. That said, I thought that it was an interesting story about a lens and cheap filters - in particular something that I really never thought about or considered.
The filter - scratching the front lens element. Quote: Here at Lensrentals we see lenses come back with scratched front elements every so often. Not a big deal, it happens. But since the Canon 24-70 f/2.8 Mk II lens came out we’ve seen a whole lot of them come back with scratched front elements. The weird thing was it was always in the center of the lens and often circular in pattern like the one below. (Ignore the dust, this front element had been taken out for replacement and sat on my desk for an hour before we took the picture.)