mDNS and Bonjour via Wi-Fi on Surf SOHO MK3 (v8.1) and Chromecast Problems

Does the Surf SOHO MK3 support mDNS and Bonjour over Wi-Fi? This thread: Surf SOHO mDNS/Bonjour on WiFi indicates mDNS/Bonjour on the SOHO only works via Ethernet (and only after UPnP is enabled), and @stego reports (Bonjour Forwarding Setting Missing?) that Bonjour forwarding isn’t supported on the SOHO.

I’ve been banging my head against a wall for months trying to get Chromecast audio groups to work on my Surf SOHO MK3 with no success. They work fine on my nearly 20 year old Netgear router and 16 year old Netgear Wi-Fi Access Point, so it is clearly something wrong with the SOHO.

Can anyone confirm whether mDNS/Bonjour work properly on the SOHO via Wi-Fi? If so, do they work with UPnP/NAT-PMP turned off?

Has anyone been able to get Chromecast devices (and specifically Chromecast audio groups) to work on the SOHO via Wi-Fi? (Individual devices work fine, and I can cast to any individual Chromecast device. But the audio groups feature doesn’t work and devices randomly stop/start playing–presumably because the devices have trouble finding/maintaining connections between each other.) All the devices are on the untagged LAN (not a VLAN) and I have tried with and without IGMP snooping enabled. SOHO reports all devices have a strong signal, and there are no Wi-Fi interference issues.

I’m about ready to give up and buy another company’s router (and stop recommending Peplink to my friends/colleagues).

Can you help, @sitloongs @Cassy_Mak @Alan @Sam_Norris @JamesPep @Mandy_Siu @TK_Liew @WeiMing @Kenny

Thanks!