To me, that always looked like a BGS mechanic to avoid two unsupported Factions enter an endless, perpetual series of Conflicts.
Then, the BGS drops them in Influence until they eventually reside below the minimum Trigger threshold, effectively ending their Conflict potential.
Apologies, FalconFly, I've had second thoughts overnight and I think you might be on to something.
I had inferred from QA-Mitch's reference to players on other platforms in his answer to the bug report that he had missed the point. What if:
I've checked this out on our end and it looks perfectly normal.
is exactly the right answer. There has to be a reason for this apparently aberrant behaviour.
1 This pattern of or regular influence losses/gains is only seen in Wars. By definition, at least one of the combatants must be an immigrant faction.
2 I don't have enough long-term records to say that regular gains/losses occur in every War. The pattern can more easily be seen in the backwater systems where influence hasn't changed for a time, but it's possible that it's always there, hidden by other activities that certainly do leech from the conflict.
If it isn't always present, let's theorise a hidden bucket that only empties and triggers the pattern after certain criteria are met.
3 FalconFly: 'The BGS drops them in Influence until they eventually reside below the minimum Trigger threshold, effectively ending their Conflict potential.' If this doesn't happen after the required number of days (see the MottiKhan's original question on this thread) and there's no external influence to interrupt the unchanging flow, the War starts up again after cooldown. Eventually, neither faction has enough influence to start the War again and may even have reached the point where one or both are forced into Retreat.
Clearly, shorter Wars speed up this process.
4 Conclusion: This is a mechanism designed to ensure that previously-loved factions - once the numbers are aligned - don't maintain a dominant position and eventually retreat to their homelands to be forgotten - until the next time - leaving room for more vibrant factions to grow.
TL;DR: Galactic society churns, even without help.