A SegmentNotFoundException is returned when a segment is not present while any activity attempts to read the node. There can be different root causes for this:
1.The segment has been removed by manual intervention (e.g. rm -rf /).
2.The segment has been removed by revision garbage collection.
3.The segment cannot be found due to some bug in the code.
We had some issues with online tar compaction with 6.2 & early versions. We even advised to disable online tar compaction in <6.3 . The documents you might have referred might be for previous versions.
there are variety if reasons for this situation. It might be caused due to long running JCR sessions along with online compaction . It can be caused by some older issues in Oak , ... etc. So the logs should shed some lights on the probable cause(s).
If none of these possibilities could explain why you got the SNFE, I would recommend opening a ticket with the support team to assist further. If you have a reproducible scenario, it would be even better.