New Speaker Is Muted When Second Call Arrives

Jan 1, 2016
I have xiaomi redmi Note 2 for 2 month and since I have it, there is a bug that when I am on a call with someone, speaking through headset or the speaker, when a second call arrives the sound output switch to the phone funnel(/receiver /ear piece, or what ever that called). This is clearly a bug and it reproduced even in the last version (24.12),
Is it a known issue?