body armor movement speed penalty?

Any one know why Glorious Plate and Assassin's Garb does not have movement speed penalty but Vaal Regalia has penalty?

I am only able to find very old patch note :

"

Body Armour now has a 3% movement penalty, with Strength or Strength/Intelligence armour having a 5% penalty, instead of 4% and 8% respectively.
Plate Vest only has a 3% movement speed penalty, rather than the 5% that other Strength armour has.

Huh. Never noticed this before, also I have assumed every non-STR body armour had -3% penalty, which goes up to -6% with STR body armours.

I guess they made it with Assassin's garb as to make its bonus on movement speed actually effective, rather than counter a potential movement speed penalty from body armour. I don't think it is the case, since Corrugated Bucklers (the shields from Act1 with movement speed) does not work like that - rather, their +3% MovSpd counters the -3% MovSpd penalty.

Glorious Plate just baffles me.