Rim was checked and it's fine, no perceptible buckle. I've resigned myself to running these tyres down with tubes and then switching to either Schwalbe Pro One or Pirelli Cinturato.
Looks like Michelin have discontinued these tyres so there's maybe something to that...
Slight buckle in the rim somewhere? Some tyres are just shit though, and don't take kindly to being run with tubes or being refitted