The union representing Tesla workers in Buffalo has withdrawn charges that it filed against the firm with the NLRB. Union allegations against Tesla accused the firm of retaliating against employees who were affiliated with the union. As of now, the union has not offered any kind of explanation regarding why the charges have been dismissed. Tesla has called the allegations illegitimate previously, and has not said anything further about the matter beyond confirming that the union chose to withdraw the charge.
See "Union drops allegations against Tesla with NLRB", Matt Glynn, The Buffalo News, September 26, 2019