What was the average bet size of your session? At first, the feature paid based on the bet size of the round when the feature was launched. Because the feature was cumulative by nature, this could be exploited by the players, one forum member managed to exploit €300k this way, but obviously he was busted when the casinos and RTG took a closer look to his play log.
https://www.casinomeister.com/forums/threads/dream-run-at-acredited-casino-intertops.60347/
To prevent exploiting the cumulative nature of the feature, the feature should pay based on the average bet size of the gaming session. Don't know if they have fixed it yet. So it might be that the displaying of the feature win is still bugged, so that it showed that $1,525 based on the current bet size, but it paid based on the average session bet size $681. So if your bet size during the spin when the feature was launched was considerably higher than the session average bet, about 2.24 times higher, that $681 win could be actually be correct. Or maybe it is totally bugged still and that $681 is too small win.
Anyway even if it just shows the feature win wrongly, and calculates it correctly, this bug should be enough reason for the casino to make the bet size invariable, like $1, or totally take the game down from their site, it just confuses customers and increases customer support work burden.