Its just MRS with bile salts? or?
It is possible that you get precipitations, not everything can be autoclaved, so sometimes you need to filter sterilize it.
Not sure about this one though.
MRS itself should not be a problem, so I guess its the bile salts.
I know there are some media out there with bile salts that can not be autoclaved, but I doubt its because of the salts.
What you were thinking is good: autoclave the MRS first, check for precipitations (if there is none, then its the bile salts thats cuasing it). After autoclaving it, let it cool down and add the bile salts using a filter in the laminair flow.
Make sure to work sterile.
(its the same with adding antibiotics : you also add those after autoclaving the medium and letting it cool down)