During google duo call, the phone frequently switched from Wi-Fi to mobile data, despite being close to the home router. While all my other devices do not have this problem. Watching YouTube or using other apps on Wi-Fi do not have this problem, so not sure whether this is app specific.
The other problem is low input audio quality. During a video call, other party frequently report unintelligible words.
But over all I love this phone for its sustainability. You barely can’t find phone like this any more.