Hi, were you able to fix it?
I have a device that is sending thousands of join request with the same error as your device.
I also deleted the device_activation entries in the network server db (https://forum.chirpstack.io/t/validate-dev-nonce-error/1176/6) . still the problem exists.
The device is a professional metering device - cannot change anything of the code of the device…
Would be great if you could share your solution - hope there was…
Andreas.