I updated my Netgear R6220 from 18.06 to 19.07.1 and found that streaming music from our Logitech Media Server (aka Squeezebox) to multiple players stops and buffers every few seconds. I downgraded back to 18.06 and it works perfectly again.
Not sure what changed in 19.07, but LMS has it's own protocol (SlimProto) and seems to have issues on weak WiFi networks (not the case here), where players can get out of sync. http://wiki.slimdevices.com/index.php/SlimProtoTCPProtocol
I do not see any obvious changes in the release notes that would cause this. Is it simply that my router has little memory left for buffers with the larger images?