WORKAROUND - I know many have been frustrated by this. I think I've stumbled on a workaround. I'm doing a dual extruder print of nylon and flexible filament. The print is entirely nylon on the first layers, then a bit of either, finished by only nylon. I require an ooze shield, prime pillar, and brim.
I created a "first layer" process that has a brim attached to the part (0 distance from part), included a prime pillar, but no ooze shield. I set the layer height to .2 mm, and set the "stop printing at height" to 0.3. Yes, 0.3, not the 0.2 layer height. This creates a brim and a prime pillar, but the prime pillar was only sized for one extruder. (The prime pillar will be the right size for subsequent layers). In order to have material under the eventual second half of the prime pillar, i made the skirt large enough to extend the width of the second half of the pillar.
For the remaining dual extruder processes, I set the "start printing at height" to 0.2. Yes 0.2, vertically overlapping the "first layer" process. In these processes, I removed the brim, but added the ooze shield and kept the prime pillar.
Success! The brim runs under the ooze shield and attached firmly to the nylon part, significantly improving print quality. The ooze shield sits on top of the wide brim, and attaches firmly as well.
Note, when preparing to print, you will be warned about the overlap. I ignore the warning and it works.
I don't know if this is a quirk that might be "fixed" in a future version, but it seems to work for now.
I provide this for people waiting for a proper fix, but I would really like an "attach brim to model" option. It would make life so much simpler.