Having spent £1,460 on a new iPhone 15 Pro Max last December, four months on it starts rebooting unexpectedly. Genius Bar in the local Apple Store diagnoses it as a failing mother board. It is repaired quickly at no cost to me, but 4 months and the motherboard fails? It has been in a Mous protective case since purchase, and has not been dropped, bumped, thumped, or even put down heavily. Has anyone else experienced this problem? Have I just been unlucky, or is Apple's quality slipping?