On the picture's you see what will happen for every different construction with the "Comparator"

Full Explain of picture:

Picture 1:

Comparator 1:
Comparator 1 give no pulse, and 1st and 2nd torch stay off when on picture 1 the rest go on!

Comparator 2:
Comparator 2 give a short pulse, and 1st and 2nd torch stay on when on picture 1, comparator 1 stay off!

Comparator 3:
Comparator 3 give a short pulse, and 1st and 2nd torch stay on when on picture 1, comparator 1 stay off!

(When you look on comparator 1 the block of redstone is 2 blocks far, when you look on
comparator 3 the block of redstone is 1 block far. And only on comparator 3 it's on!)

Picture 2:

Comparator 1:
Comparator 1 give no pulse, and 1st and 2nd torch stay off when on picture 1 the rest go on!

Comparator 2:
Comparator 2 give no pulse, and 1st and 2nd torch stay on when on picture 1, comparator 1 stay off!

Comparator 3:
Comparator 3 give no pulse, and 1st and 2nd torch stay on when on picture 1, comparator 1 stay off!

(When you look on comparator 1 the block of redstone is 2 blocks far, when you look on
comparator 3 the block of redstone is 1 block far. And only on comparator 3 it's on!)

Conclusion:
I dont think this have to do with the Physics and Logics of the game. I think this is a bug
because it give a short pulse when you place a power source like the "Block of Redstone", This can
conflict with future systems/machines, because when you want to get a comparator to get a redstone signal from
behind, but the side port did not give permission to give a redstone signal to the rest of the system/machine, but
it because it just let a short pulse trough the comparator, it can conflict and give the system/machine a kind
off system crash that it cant follow what to do for "EXAMPLE".