The herringbone has to come out because the preslope wasn't done properly. There is a hump on left side of the drain. Water will pool at the left wall. Also, that's thinset between the tiles and the the drain sits higher than the tile on the right side. It's a disaster.
Previous installer works for a tile company and was doing it on the side. He was def in over his head. I'm assuming he's not a true installer and is just an assistant.
The yellow stuff that is combed was already there. The pan never had problems with leaking but the preslope was off a little in the corners. No water damage behind the walls though.
The first guy chipped up the tile, laid self leveler, put a vapor barrier on the floor only then laid tile on top.
I questioned him at this point about drainage and he said he could freehand it with thinset. (yeah, really...) I should have stopped him there, but I didn't know how bad it really was. After the disaster on the floor I had some real pros look at it and realized I was screwed.
Now here we are
I was afraid of this & why I kept asking about pan...
between that *plumbed* wall & this job,
you've had a real screwy month..
In conclusion, nope; I don't believe you really
need to worry about red guard corners