Brand's passive with Rylai's and Liandry's - Every other proc misses out on slow bonus

If you test it in a Practice Tool game on a dummy and watch the numbers, you can observe that Brand's Passive, Blaze, re-applies the Rylai's and Liandry's debuff each second, but for some reason, every other half-second-tick of Liandry's is one without the slow bonus damage -- the tick that occurs each second when the debuffs re-apply through Blaze. This must be because it is 'checked' for in-between the re-applied Rylai's slow ticks, although it doesn't seem to me like that would be intended.

When Rylai's is applied from another source, and I see the debuff icon refreshing before the 1s duration is through, the Liandry's bonus damage ticks normally.

I've started looking for and testing other damage-over-time abilities that tick once per second. So far, Mordekaiser's R does not have the problem of Brand's passive even though it seems to mechanically interact the same with these items. Same with Trundle's R.

On Brand, when I get the Rylai's re-applying multiple times a second, I believe via multiple stacks of his passive, it seems to do so at odd intervals. Also, I've now seen that there is some talk of Blaze operating a bit peculiarly timing-wise, so this might be the reason for its issues with Rylai's + Liandry's. However, when I use the passive with Rylai's on something and watch its movement speed value, it never wavers from its lowered value through the whole duration.