Three codes were hidden in the WITNESSING THE MIND PALACE post on the Investigate Ingress blog.
[1] 2xjn3easyb2r7r
[2] 9e34scir8hqxhhtm
[3] <!!<%^!!<%%%<%%!<!!<%%!%<%%%^<%%%!^<%%%!!!<%%!!!<%^!!!<%!%<%%<!!!<%%^!!<!!<%%%^!!
Code #1
Observations
Everything is there but why does it return invalid ?
Code #2
Observations
16 characters with the right amount of numbers for a valid passcode
Code #3
Observations
Find the split character. Why do you have only 4 distinct characters