Castbar on an already casting enemy's nameplate

Hello everyone,
I run into a singular issue recently trying to set up some addons for the new server Onyxia, and I hope somebody can shed light on this.
I'd like to have the castbar of my Target placed below its nameplate, and I tested different addons which were all working as intended (Tidy Plates and Kui mostly).

However, I noticed that if I target an enemy when it already started casting the bar is not showing at all. Basically, either the target starts casting when I am already targeting it, or I cannot see the enemy castbar (which makes switching targets detrimental).

I tried also to disable all addons and use the blizzard default option which puts the castbar below the nameplate, but I had the same problem regardless.

Is it a standard issue in wotlk? Or is it just me having this problem? Anyone knows a fix (if there is any)?

Thanks a lot!

Mardy

It's a limitation of the wotlk client.

Eh, I feared that but I just wanted to be sure I guess..thanks for the quick reply though!