Participant will lost audio when new participant joining

Having two frustrated issue right now.

1. Some of the participant will lost audio (even though audio still show connected) when there is new participant join the meeting. 

2. Part of participant will be muted when new participant join (mobile user have reinstall Zoom and updated to latest version, although zoom setting have de-select "Mute all participant when they join a meeting".

Please help on this as this major issue.

Cheers.