Hello!
I have MikroTik with hotspot (it doesn’t matter with the default config or redirect to the external page), I have a several iPhones, with the same version of iOS (the last one), some of them captive are triggered, others aren’t. And from time to time the captive still opens, but an Apple.com opens in it. With Walled Garden I tried several options, just left it clean. Help, a month can not find the cause.