Q. Rov, I was attending a Maariv minyan at an Avelim home and after Maariv they counted Sefira. For some reason one of the attendants incorrectly corrected the fellow fellow that counted, but he himself was wrong in the date and the attendants didn’t pay attention, until later when most of them were gone. Did they have to be contacted to set them right?
A. Poskim rule that if one counted correctly the first time, even if he reversed himself immediately the first counting stands since it was correct. (See Shulchan Aruch 209: 2, Mishna Berura 46: 20, Nitei Gavriel 35: 11, and others).
Horav Shlomo Miller’s Shlit’a opinion is similar.
Rabbi A. Bartfeld as revised by Horav Dovid Pam, Horav Aharon Miller and Horav Chanoch Ehrentreu Shlit’a