This is the proper etiquette.
Su Luo has complex feelings toward the old lady.
When she was still a Crown Princess, she quite liked the old lady.
Back then, the Empress Dowager showed a lot of care for both Wei Shu and her, even giving her a token that aided her in times of danger.
When did things begin to change?
Probably when she became Consort King Huan.
That time, the late Emperor wanted Wei Shu to take Liu Mianmian as a concubine. Both husband and wife openly resisted, yet the Empress Dowager persuaded them to agree.
From then on, Su Luo felt estranged from the old lady.
But it was still understandable.
After all, she was in the Royal Family, and she considered things from a different perspective.
However, after Su Luo became the Empress, her recurring attempts to match Liu Mianmian with Wei Shu piled up discontent in Su Luo's heart.
Even the Empress Dowager's occasional offering of expensive gifts to ease tensions could not bridge the chasm in Su Luo's heart.