The problem you are running into is due to IP redirects. IP redirects can be good or bad depending on how the PCs handle the redirect packets.
It appears the hosts on vlanZ might be using the gateway address of 10.1.1.1. The switch would be sending a ICMP redirect packet to the hosts to forward the traffic over to the core router. Sometimes it works and sometimes it doesn't.
Try adding this config to the switch and see if that resolves your problem.
We are pleased to announce availability of Beta software for 16.6.3.
16.6.3 will be the second rebuild on the 16.6 release train targeted
towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are
looking for early feedback from customers befor...
Introduction Featured Speakers Luis Espejel is the Telecommunications
Manager of IENova, an Oil & Gas company. Currently he works with Cisco
IOS® and Cisco IOS XE platforms, and NX to some extent. He has also
worked as a Senior Engineer with the Routing P...
In this session you can learn more about Layer 3 multicast and the best
practices to identify possible threats and take security measures. It
provides an overview of basic multicast, the best security practices for
use of this technology, and recommendati...