Sisters of Battle are being done. (Including plastic sisters .... obviously!)
I first heard the project was started over 12 months ago.
If that is correct they are more than 12 months into the project.
Given lead times of 18 months on the plastics by now most of the sculpting for the plastics should be done (not just the sisters) and the first kits will already be finished.
When they make plastics they make a few which come back to the sculptors to be 'checked' and given the OK before they start making gazillions (I can't think exactly what they call this off the top of my head). But they are looking for any little bits and bobs that need sharpening up, stuff they are not happy with or didn't come out exactly as they should have ... so they can go back and fiddle things a bit. (to ensure we get the best possible final version).
So this has almost certainly happened with some of the plastics for sisters by now.
But the existence (or not) of a little something the sculptor wants to change or tidy up a bit is not a problem. it is just a normal part of the design process. (a normal part of producing the world best toy soldiers).
It is no more an issue than correcting a spelling mistake or changing a word to increase clarity when proof reading a book.
"Delays" are often NOT delays. Things get made then sit around the studio for months sometimes years. (If you look back at the rumours articles in the Watchman from a couple of years ago I was talking about the completed Clan rats that have only recently seen release). Stuff is not delayed it is waiting. Waiting for more stuff to be made to go with them to make a decent release, sometimes waiting for a release window when they will not be competing for sales with too much other stuff. So not delayed just not released yet.
The point is that just because something exists and isn't released (sometimes for a while) does not mean there is a problem with it.