I have stack of 3750s running advancedIP image, and a 3550 running IPServices. Both are running IP Routing and are apart of per SVI HSRP groups. The switched infrastructure runs rapid-pvst, where the 3750 stack is the root. The 3750 is also the active gateway in all HSRP groups. EIGRP is the routing protocol. The 3550 can only ping its neighbor switch (not the active 3750) and no others devices in the management vlan. It can ping everything else in all other vlans. When it becomes the active gateway for all VLANs, everything on the management is inaccessible except for itself, and its directly connected neighbor. Furthermore, while the 3750 is active the 3550 is accessible from some of the switches in the topology, while connecting to others makes it unreachable.
So far I can find no reason why this should be happening. Anyone have an idea?