error correcting codes – Even parity applied on bits, that don’t follow the rules of even parity

The following example is given:

The sender and receiver are using 1 bit even parity
The sender is sending 1110 1010 over a noisy channel.

in case 1 the receiver gets 1110 1100

in case 2 the receiver gets 1110 1001

Which one of this two cases was detected and why wasn’t the other one ?

I don’t understand how one error can be detected and the other error can’t. Both have the exact same number of o’s and 1’s. Can somebody explain this to me?