WiFi issues with cordless phones and Orbi

After a lot of debugging and some internet searches, I suspected the upgraded modem hardware. I completely removed the orbi network and hardwired to the modem after taking it out of bridge mode to verify. Per suggestion from comcast employee post and private message, I went to a local store and traded the sick xb6 for a specific xb7. It turns out that a lot of arris modems with the intel puma 6/7 processor have dropping problems. There are a lot of web pages that are dedicated to this problem and list the modems to avoid.Search for "bad modems puma". The xb6 and xb7 models handed out by comcast come from two manufacturers, some use the puma processor (arris) others use a broadcom (technicolor) - note the model number on the bottom. I asked for and they had a xb7 with the broadcom and have not seen any issues previously reported. Background: the pumas cannot keep up with the load and cause drops, lags, and increased network jitter. My VPN connection saw that and disconnected. The VOIP call triggered additional load and accentuated the problem. Thanks for all your suggestions, it helped me narrow down the issue. In the end, not an orbi/phone issue but wanted to post an update. Cheers.