IPv6 Xfinity R7800 DNS/IMAP/POP/TLS stops working Android

When I enable IPv6 on my R7800, DNS/IMAP/TLS/Xfinity Connect/Stream/MyAccount stops working on Android phones if I leave my home wifi and come back.... Everything else works on the phones - internet browser, google play, youtube, sirius radio, gmail native app, yahoo email native app, etc. All Windows 10 Laptops on the same home wifi are not affected.

Xfinity gigabit service.

Arris SB8200 modem.

R7800 firmware v68 and v80.

Why do Android clients DNS/TLS stop working when IPv6 is enabled on my router? Specifically when I leave my home wifi and come back. The only way I know to remedy is disable IPv6 on the R7800, unless someone here has some ideas???