Three codes could be found in the TECTHULHU EXPERIMENT post on the Investigate Ingress blog.
[1] ik373esa27eld
[2] 838374535213555552557177
[3] B2z3mZLHAtu5m3HL
Code #1
Observations
Passcode format is there but reversed, dashes will help you
Solution
Code #2
Observations
All numbers, there is a pattern in there expect for the central part
Solution
Code #3
Observations
20 characters, capital and lowercase letters and numbers. Usually it’s 24 but 20 will do just fine
Solution