My phone occasionally switches from normal mode to speaker with no warning. It can be at the start of a call I make or receive or during a call. Easy to switch it off, but I’m wondering if there is some way to keep it from happening. I first noticed it about a month ago.
You may want to follow this Help Article and Clear Cache … with intermittent problems, often time a ‘bit’ can get set by an app or the system itself, which when the exact same conditions occur a problem will re-occur
If possible we should clear both system and application app