I also have this issue. I’m not keeping very many stats so I can afford the “hard way”. I’m commenting to give my insight in case it helps you find the issue faster:
My custom player statistic S is a linear function of player performances, one of which is custom P. The function looks like S = 50*P + … Say P = 2 and S = 200. On the player page it will correctly show S = 200. On the player list page it will show S = 202. If P is changed to 1, the player page will correctly show S = 150. The player list page will show S = 151. Even if I don’t include P in the equation anymore (effectively S = 0*P + …), I will still get S = 100 on the player page and S = 102 on the player list page.
All that to say that I think in general it’s not doubling; it’s calculating the statistic with a weight increased by 1 (0*P –> 1*P, 1*P –> 2*P (doubling), 50*P –> 51*P).
