VOIP has a limited amount of concurrent clients talking before packets start to get dropped.
If more than two people are speaking at once, host will see log:
[2016.10.05-17.37.25:122]LogNet:Warning: Network saturated
[2016.10.05-17.37.25:123]LogNet:Warning: Dropped 1 packets due to congestion in the voicechannel
Voice Chat Cutting In/Out
4.13 Steam Setup Not Working
VOIP unstable on Steam: 'Network saturated'
Head over to the existing Questions & Answers thread and let us know what's up.