Packet Loss on IPv6

Hi

I'm on Pano WiFi and has been experienced annoying connectivity/latency issues, most prominently in voice/video calls over whatsapp and the like. It is bad to the point when switching to LTE (with 1 bar signal) makes it much better.

I'm positive that WiFi is fine, as I have same problems over wired connection as well, plus speedtest is happy.

Today I was looking at PingPlotter and I noticed that there's huge packet loss when using IPv6, while IPv4 is fine:

To verify this, I took my rooted Android phone and did "echo 1 > /proc/sys/net/ipv6/conf/all/disable_ipv6", which essentially disables IPv6 at the OS level. Verified with http://test-ipv6.com that it indeed got disabled and then checked problematic apps.

I think this has "resolved" the issue for me. Now the question is, how to get a proper fix? I wouldn't like to go over all of our devices and disable IPv6..

Thanks