A pictured and featured cast member on SVU

Tamara T was a steady presence on L&O: SVU for goodness knows how many seasons, but I notice during season 7 / 2006, she (as well as Diane Neal and somewhat surprisingly, BD Wong, unless I'm mistaken) has a still photo among the featured stars and is in the group photo that's so much a part of the opening sequence for the show.
Which is to say, she was a featured cast member, as opposed to simply having a recurring role with secondary credit.
However, I believe she continued with the show for many more years while being sort of demoted back to secondary cast status.
I imagine for a time the writers were inspired to increase her role and lines, then dialed it back when they chose to focus more on the main cast.
But it seems unusual to make someone a featured cast member then keep them around after diminishing their status. And while often her role was confined to a few critical scenes, she was always a welcome and vivid presence when she was on screen. She exhibited a sort of warmth and intelligence that made the other characters very aware of her value and competence.

In other words, on SVU Ms Tunie seemed pretty cool to me.