Jay-Z’s latest concert at Yankee Stadium hit setbacks after fans noted tech failures . The crowd waited after their phones failed to sync . Some screens went dark mid-set. An actor filled in for Mary J. Blige after she faced an issue. Teyana Taylor stepped in later to help . Blue Ivy Carter played piano for part of the show. Dame Dash then claimed Jay-Z’s latest stadium gigs felt more like product demos than genuine concerts.