Well that last Powerplay CG had week 2 add some "spice" which resulted in Frontier taking the outcome as "system went back to Powerplay unoccupied" so there might be something for this one as well.
I'm not sure Frontier touched the Powerplay state of that system manually at all at any point
Starts: unoccupied, with only Grom, Winters and Archer in range to claim
Week 1: CG participation (and related activities) boosts Winters more than Grom, Winters takes the system, Archer well behind, contributions from the other nine powers irrelevant
Week 2: CG participation (and related activities) can be an undermining action for 11 powers and a reinforcing action just for Winters, Winters loses the system again
Mining is unusual in that it's a CG action and a reinforcing action and an undermining action - for trade or bounty CGs, the CG action reinforces but cannot undermine, so as we see here both powers have reinforced control of their CG system even though they're theoretically facing a lot more undermining players (including the interesting touch that each CG is in a system of the opposite power).
It also doesn't help that a good chunk of the Kaine followers are actually very pro-Mahon, so minimal motivation to push hard to make it a real contest. Not too long ago I was told by one such that the lore where Kaine is antagonistic towards Mahon didn't matter at all
Also the CGs don't have any obvious Powerplay effects
- you get 5 bonus ranks if your side wins, but that's mostly out of your control and most of the serious "in it for the Power" CMDRs will have got rank 100 anyway by now.
- there's no bonus to the power as a whole for winning, or indeed penalty for losing, so if you want your Power to win systems you can just keep doing that for two weeks.
- it's not even all that likely to change ownership of either CG system, and even if it does it's only one system
I think they're more to potentially attract newer players into Powerplay and encourage them to pick a side.