Oneplus 6T OTA continually fails

I have a Tmobile OP6T and the OTA has not worked for the last several releases. I disable all security, encryption etc. and download the update. update goes through installation and verification but when I reboot the phone hangs in a bootloop going to the boot loader. I can force it to enter the recovery(stock recovery) and update via ADB. After ADB sideload it reboots perfectly with all of my data saved.
ADB is no big deal but the OTA has worked on my other devices before this. I saw older posts with related issues but no clear answers about the solution.
Thanks in advance for any help.
The Colonel

Regain your privacy! Adopt /e/ the unGoogled mobile OS and online servicesphone

Two months and no ideas?