First, by law, they can not accept any new 485, if visa numbers are exhausted for a FY. It does not matter if they released conflicting visa bulletins. Therefore, the law suit will not survive.
Please read all the ombudsman report for last few years 4 or 5 times before posting here.
Immigrant group (and lawyers) and USCIS have completely conflicting interests. USCIS which had history of slow processing of application. Now it got severe criticism by ombudsman to approve 485 on time. They set the processing goal for 485 as 6 months. The recommendation of ombudsman is, if they can’t approve with in six months, do not accept any new applications. Ombudsman strongly recommends abolishing (the need for) interim benefits like EAD, AP, if 485 approved in 6 months. In fact, he recommended a procedure to get a green card in one day. See the flow chart in his report. Based on his reports, USCIS is going towards perfection to approve 485 on time.
On the other hand, immigrant group and lawyers have completely opposite interest. Their interest is not the GC. Their main interest is EAD, AP and AC21. They do not mind if they get GC after 10 years, as long as they can get EAD, AP and enjoy the benefit of AC21. Lawyers will enjoy continuous legal fee the as long as 485 is held for prolonged time.
USCIS can not flex their procedure just to honor the hidden agenda of the other groups. The other group wants the USCIS to continue the mistake they did past, and want to reap the benefits out of mistake of wrong Visa Bulletin (all current) on June 12.
The law suit is not the solution. All leading law firms say that there is very less chance to win the suit. The only solution is need of more EB visa numbers, to meet the demand.