Builds on the node-vs-node fix: a node's GUID is now also treated as ambiguous when it equals the master's own panelGuid (a node cloned from the master), so the master's local clients and that node can't merge. Centralized as ambiguousNodeGuids(nodes, selfGuid) + effectiveNodeKey(node).
Applied the same node-unique fallback to the GUID-keyed IP attribution that #4983 added but the prior commit left collapsing: MergeClientIpsByGuid remaps a cloned node's own subtree to its node-unique key, nodeGuidNameMap resolves names by that key, and node deletion purges both keys. Added a throttled heartbeat warning so the operator is told to regenerate a duplicate panelGuid. Tests cover master-collision, effectiveNodeKey, and the IP remap.
#4983 keys online/inbound attribution by panelGuid, assuming it is globally unique. Cloned node servers ship an identical panelGuid in their copied settings, so the master collapsed several physical nodes into one bucket: GetMergedNodeTrees merged their online sets under one key and every inbound on those nodes (same origin_node_guid) read that merged set, so the inbound page showed online cross-attributed and counts inflated.
Fall back to the node-unique synthNodeGuid(node.Id) whenever a node's panelGuid is shared by another of the master's direct nodes. Applied consistently at originGuidFor (origin_node_guid write), the online-tree key plus a self-key remap for nodes that report a GUID-keyed tree, effectiveNodeGuid, and recountByGuid's inbound bucketing. sharedNodeGuids computes the collision set. Online now works without node changes; making panelGuids unique restores real-GUID identity and also fixes GUID-keyed IP attribution.
MHSanaei