https://wccftech.com/iphone-11-randomly-disconnects-from-lte-in-dual-sim-mode-are-you-affected-too/

Whether it's an iPhone 11, iPhone 11 Pro or iPhone 11 Pro Max, the smartphone randomly disconnects from LTE and reconnects again while using dual SIM.

Despite being blockbuster phones for Apple, the iPhone 11 and iPhone 11 Pro come with their fair share of issues. For example, if you make do with FaceTime a lot, then you might have noticed the phone falling back to LTE and disconnecting from Wi-Fi completely randomly. Now it seems there's a new bug on the block, and it will only affect you if you have dual SIM enabled.