My New S21 kept doing that, and callers not hearing me or me not hearing them ! 3times it went back for repair, I ended up sending it back to the supplier telling them exactly what Trading Standards told me, The supplier wanted me to pay evermore for the S21fe, I was fuming. Spoke to Citizens Advice notified 3 and hey presto they gave me another deal"" yet I still lost 3 months payment of the S21.its obvious Samsung knows of this fault after reading here and other websites. Why don't they just recall rather than get a bad reputation?