There have always been a recurring event of Samsung flagship phones developing a bug. And Samsung’s latest high-end flagship S9/ S9+ hasn't been fortunate to escape this almost 'ought-to-be defects'.
The Samsung S9/S9+ has been reported to being problematic with the call function. According to a Samsung Polish community spokesperson who confirmed the failure, when the failure occurs, only the other call party can hear the sound and that this defect lasts for about 20 seconds.
Some users feedbacked that the S9 they use will be disconnected after a few minutes of talking. The later is less reported as the former. This signals that there may be other bug apart from the ones related to calls affecting this veersion of samsung.
Samsung has also recently released an update to improve call stability, but that doesn't solve this problem. There is also an issue of not receiving missed call notification. The issue is believed will be fixed for the dual card version of the Galaxy S9 at the next update.
The Samsung spokeperson stated that the company is diagnosing the problem and developing patches.