According to an e-mail just received from Rabbi Yudel Shain:
The Mezonos Maiven wholesale bakery in Brooklyn under the "OK" & Hisachdus was caught by a group of frum yidden operating on Shabbos Parshas Shoiftim (Sept. 10th) at 6:30 PM.
Consult with your local rabbi regarding any possible kashrut concerns or questions regarding kaylim. Check with the OK to determine the veracity of the report. (Realize there are ways for a kosher bakery to operate on Shabbat, and Mezonos Maven may have arranged this with the OK. Your local rabbi should be able to determine if this arrangement had been made.)