Given a KB with the two rules below:
The rules work normally in the first session created from the KB.
When any additional session is created and used, the SegmentMemories are restored from the SM Prototypes.
Unfortunately, the AccumulateNode -> RuleTerminalNode segment is restored twice, once when the "aaa"
triggers the appropriate Beta Node, and once when the subnetwork updates the RIA node.
The latter overwrites the already existing segment, overriding the partial link bits.
See SegmentUtilities line 421, where this tentative patch shows the problem: