Delay acting randomly

[LemADEC]

When using /qc quantum or /qc reverse with a delay, the results are more or less unpredicable.
1st test:
source = redstone dust powered by a daylight sensor
receiver = 10 pairs of levers spaced by 0.2s between each pair (0 0 0.2 0.2 0.4 0.4 0.6 0.6 etc.)
observed: first pair of 2 levers reacts properly, all other will switch on but will never go off

2nd test:
source = redstone dust powered by a lever
receiver = 5 levers all triggered after 0.5s (0.5 0.5 0.5 0.5 0.5 etc.)
observed: in most cases, 2 levers will randomly switch, others will remain

3rd test:
source = redstone dust powered by a lever
receiver = 5 redstone lamps all triggered in sequence of 0.5s (0 0.5 1 1.5 2)
observed: all will switch on but never goes off

During all testing, I've seen nothing special in console.

Reversed seems to work with 2nd and 3rd test but still fails the 1st one.
When using no delay at all, it seems much more predictable (so far).