Hi,
thank you for pointing out the issue with this error. We will improve the messages in order to simplify the process.
The error is due to the fact that the nucleation on layer 1 in your design has 2 inputs, and the number of inputs must be odd.
It is correct in the second design because the pad will connect only with a nucleation in front of it. You can have a look to the documentation for the table describing all the connection for each element.
Umberto