Fyi my sim2 IMEI comes up "device id you entered is not compatible with the Verizon wireless network." Put the same sim in slot one and VZW recognizes the device as a compatible OnePlus 6T (incorrectly saying it's an 8/256GB - actually an 8/128GB Thunder Purple). VZW postpaid account.
Full story: Got my device, pulled sim from my N6P and randomly put it in the sim2 slot of the 6T. Phone recognized VZW, showed VoLTE and signal. Chat to activate CDMA_Less could not locate or activate it. Said they'd have to get back to me. I later tried to self-activate as suggested in #2 on this post by OnePlus staff and the IMEI came back "device id you entered is not compatible with the Verizon wireless network." Got the same result checking it on the VZW bring your own device page. I then tried the IMEI for sim1 and it was recognized as VZW compatible. Swapped the sim into slot 1 and chat was able to activate CDMA_Less almost instantly. Now have full SMS; Have not tried MMS or group yet.
Full story: Got my device, pulled sim from my N6P and randomly put it in the sim2 slot of the 6T. Phone recognized VZW, showed VoLTE and signal. Chat to activate CDMA_Less could not locate or activate it. Said they'd have to get back to me. I later tried to self-activate as suggested in #2 on this post by OnePlus staff and the IMEI came back "device id you entered is not compatible with the Verizon wireless network." Got the same result checking it on the VZW bring your own device page. I then tried the IMEI for sim1 and it was recognized as VZW compatible. Swapped the sim into slot 1 and chat was able to activate CDMA_Less almost instantly. Now have full SMS; Have not tried MMS or group yet.