Comparators do not normally receive one tick pulses from observers (this seems to either be a known issue or working as intended). However, If the same redstone line recieves two observer pulses on the same tick, the comparator will recieve and transfer the one tick pulse.

Using the setup pictured below, I confirmed that there seems to be no difference in the timing of length of the pulse whether there is one observer or two.

Steps to reproduce:

Create setup shown in screenshot. Update trapdoor above gold block once with only one observer connected, then again with two observers connected.

The two chat screenshots show the output of the three command blocks shown in the screenshot The dash indicates every game tick, the star indicates when the observer line is powered. Because there are only two stars this indicates that in both tests, it was a one tick pulse.

This seems different enough, but may be related to MC-109737