Device Offline Problem after 5-119 FW update

I have recently been having this weird device going offline issue with my Gen2 controller. I think the problem started with 5-119 FW update. I have had the controller for years on my current network setup and it had been working just fine.
Rachio controller keep going offline. After reseting it, sometimes it goes online for a bit and then goes offline again. (3rd light flashing)

I have done troubleshooting steps below:
Reset wifi setup several times. Connection to Wifi is fine but looks like connection to cloud fails
Controller associates and authenticates to AP and receives a local IP address. (DHCP reserved). Responds to ping as well on that address
Doing a TCP dump with grep on device IP shows constant attempts from controller to resolve on :53
Important to note that I have an advanced DNS over TLS setup on my with cloudflare but rachio worked with this setup till recently. The odd thing is that I did a dig on to make sure my router is able to resolve the domain and suddenly the controller went online. This is really weird. Having the rachio server IP cached locally should not matter. I am not sure if this is a red herring or the real root cause. Waiting for controller to go offline again to retry.
Anyway wondering if anything changes with the IP level settings with the new FW update. Is the controller trying to use a hard coded DNS server that my router may be blocking?
Any insight will be appreciated

I found this other discussion that seem to be same issue as I have
It does look like a DNS resolution bug