The issue was due to be resolved in talks this Thursday between Weinberger and Tony Wright, the new worldwide president of Lowe.
Locking in Weinberger is vital if Lowe is to keep its £42m Tesco account, which he oversees creative work for.
Weinberger, regarded as the guardian of Lowe's creative culture, has told associates he is confused rather than angry at being kept in the dark about Lace's arrival.
Mark Cadman, the Lowe managing director and the senior suit on Tesco, shares this anger. He had expected to become its chief executive.
Meanwhile, sources suggest Lace's appointment was the result of pressure on Wright by Lowe's Interpublic parent for urgent action to improve the London agency's new-business performance.
If you have an opinion on this or any other issue raised on Brand Republic, join the debate in the .