You changed your interface to not implement RFC 5735:
127.0.0.0/8 - This block is assigned for use as the Internet host
loopback address. A datagram sent by a higher-level protocol to an
address anywhere within this block loops back inside the host. This
is ordinarily implemented using only 127.0.0.1/32 for loopback.
An ICMP Ping is a datagram in the sense of the second sentence.