Why does the Real Time Availability Monitor (RTAM) sometimes publish two records/trigger two alerts?

Answer

MCF version 8.5

The Real Time Availability Monitor (RTAM) could trigger two alerts when both the "ATP Monitor Rule" and the "Node level ATP Monitor Rule" are configured for an Item (under the Inventory Info tab). Since the RTAM is capable of monitoring inventory not only for specific  nodes but also for an entire Distribution Group, it is possible that a  single inventory change causes crossing of the threshold values at a specific node as well as at a distribution group (which contains the node).

One of the alerts is raised from the "ATP monitor rule" configured. This shall consider the Default Distribution Group configured at the sourcing Basic Configuration (under Distributed Order Management -> Cross Application -> Sourcing and Scheduling).

The other alert is raised from the "Node level ATP monitor rule". This rule considers the Distribution group configured for Node Level Monitoring (under Global Inventory Visibility -> Inventory Rules -> Monitor Rules). It monitors each of the nodes in the specified distribution group.