The root of the matter was the marquis title. The imperial edict came from the Emperor himself, and the title was granted by the Emperor. But his mother, Madam Shen, foolishly believed that the title of marquis should have gone to his younger brother, Shen Qing.
Madam Shen was partial, quarrelsome, and sharp-tongued. She felt that Shen Nian was unfilial and unbrotherly and had a bad reputation, so she genuinely wanted Shen Nian to give up the title.
But Shen Nian was no pushover. He refused her outright and told her that if she was unhappy, she could take it up with the Emperor himself.