The audio sample clearly reveals that something is wrong. Significant information below is that the problem occurs only with remote traffic, not with local traffic which generally outrules local RF equipment failure.
I would look more closely the internet connection. Sounds like there is substantial but not persistent packet loss at the internet link now and then which distorts the incoming d-star datastream. The voice data is UDP, which means that there is no proper way of making sure of the delivery of each single audio datagram. I don't know has the gateway software any debug features to reveal this kind of data loss, and if it does, there will certainly be some indications of packet loss. The case could be such, that when the peak data flow on the internet connection reaches about 2/3 of its capacity, the audio UDP packets get queued and not delivered to the gateway in time, or get delivered in incorrect sequence and dropped. These are the usual causes for audio problems when dealing with Voice over IP, which the traffic between d-star gateways and reflectors looks like if not looked too closely. The problem can be local LAN equipment related hardware issue, or truly a capacity issue when your solution would be to prioritize the d-star gateway traffic over the other traffic Hopefully you willl get it fixed! 73, Erik OH2LAK
