In A7S, the boss uses an ability called Sizzlebeam, which leaves a DoT on the player(s) hit called Electrocution. The ticks of this DoT appear incorrectly on FF Logs.
In this randomly selected log, you can see the problem. The “Combined DoTs” has the actual damage value (in this case, 2800-3000), but the amount attributed to Electrocution is much lower (115). This happens in every posted log, where it ticks for some value under 256, while the corresponding Combined DoTs entry for each is much higher.
Not a huge issue, since it doesn’t affect rankings (except execution, I guess) but it does make analysis around that ability a little more painful than it has to be.